The problem is more about some players think everything is an exploit instead of letting Bioware set their rules.
Since the begining of DAMP, we've seen a couple trends, so let's examine them a bit...
Rejoining as a level 1 on wave 5
Let's get something straight, Bioware made rejoining a game without losing your XP a feature. It was to avoid the fiasco from ME3MP where players lots "Billions" in XP and Gold.
Now, the "rejoining with a level 1 at wave 5" resided in a gray area. I don't think Bioware intended the original feature to do that, but when they were made aware of it, they let it slide. Eventually, the pressure from some community members made Bioware change its mind. More conditions to keep your XP while rejoining were added and the point has been close.
At no point in time this practice was considered a cheat by Bioware. It was in a grey area, then it was blocked so it doesn't happen. Bioware didn't threatened anyone with bans, they simply corrected an unintended use of their feature.
Animation cancelling
This is a feature. Bioware coded it with that specific purpose. It was like that in ME3MP, it's the same with DAMP. End of discussion.
Spawn camping
This one is very interesting...
The thing is, it was perfectly possible to spawn camp at launch and nobody, even Bioware, cared about it. Let's be real, what "benefit" could you ever gain from that? Absolutely nothing. You need to kill things for XP and collect gold to get any progress. So spawn camping wasn't even remotely in your interest, but you were free to gimp yourself if it made you happy.
Then the Hakkon weapons arrived. Suddenly, there were items directly tied to a boss (dragon) so speedrunning thru the whole map COULD allow you to get the item you wanted faster. Because they tied the items to the Dragons, it wasn't pure RNG anymore, people could tip the odds their way by completing the games faster.
Again, after some pressure from some members of the community that saw this as an unfair advantage, Bioware decided to finally take position on the matter and made the practice "not ok". But that's not how it ended. At first, they reduced the spawn points blocking radius to a very low value. The results were pretty bad, enemies were spawning on your head and the whole game became very silly. Then, they saw their tech wasn't up to snuff so they decided to simply halve the original values which made spawn camping much harder to accomplish. In the process, they also changed their position to a somewhat middle ground between "ok" and "not ok". Thus, their positioned went from "ok" to "not ok" to "ok, but you're gonna have to work a lot for it". Bioware never threatened anyone with bans, they simply adjusted their rules with the new conditions they were facing. They even confirmed spawn camping wasn't a problem, they only acted because they tied the Hakkon weapons to the dragons and were at a lost on how to fix this without taking this workaround.
The irony here is that people that complained the most about the "unfair" advantage were the ones that got nerfed the most. By reducing the spawn point blocking radius, Bioware effectively made spawn camping impossible for low promotion players. All the while, leaderboard players, the very ones that were using spawn camping the most to begin with, are still using it just as easily and with Bioware's blessing on top of that! And nobody complains! LOL!!!
Personally, I don't think this was a cheat, an exploit or an unfair advantage. If you're strong enough to spawn camp, you already play the game enough to get the weapons anyway. Getting them faster is just a plus. If you don't play the game much and get the weapons anyway because you're being carried, then good for you. I hope you're gonna be strong enough to play with me whenever I need a PUG in my lobby. It's a win-win situation, there's no unfair advantage, it's just about putting the time and your skills to contribution.
Double XP bug (double gold)
This one was definitely a bug introduced by a patch recently released. Bioware made it very clear it wasn't intended to give players twice the XP.
Their official stance was "don't do it on purpose, but if you happen to get into such a lobby, enjoy the free XP while it lasts". At no point in time did they threatened anyone with a ban BEFORE they took position on the matter. AFTER they took position, they said there MIGHT be consequences for those abusing the exploit. To this day, we still haven't seen any repercussion for the guilty players.
Personally, I think there's nothing Bioware can do. Their tech cannot find out who did it on purpose and who never realized they did it in the first place. They do have metrics, but I doubt they're gonna be precise enough to do anything substantial about it. At most, my guess is that we might see a small ban wave for the worst offenders, but no one that benefited from that bug "normally" will ever be reprimanded. In any case, except for the leaderboard drama, it's a win-win situation for players. PUGs got stronger with promotions and the overall playerbase benefited from that. Players that complain they worked harder for that XP and it's an unfair situation are simply grasping at straws. Yes, they did work harder and there's no denying that, but then again so would someone that exclusively played Routine over someone playing Perilous. The point is moot, your "efforts" aren't exclusively quantified by how much you played on that specific period where the exploit was possible.
As for the 2x gold bug, it was blown out of proportion as this is a leaderboard drama exclusively. Gold was only counting twice for the challenges, players never benefited from more gold in their inventory.
Finally, the XP "cap" they introduced to solve the situation is a good temporary solution, but it should have been removed when the real fix for the double XP bug was put in place. It's perfectly possible to go over the cap on some maps with certain team composition. Bioware refuses to acknowledge the problem and we are being wrongly punished for that.
My personal take on the double XP bug is that it was blown out of proportion because Bioware made the challenge system the way it is. Because the challenges aren't repeatable, the only way to increase your score at a certain point is to promote. So your leaderboard rank is directly tied to how much promotes you can do instead of being tied to how much challenge you can complete. Ironically, nobody complains about that. People instead complain about the playerbase becoming stronger and not dying all the time...
Rejoining a game on Heartbreaker after being in the fade
Since the launch of DAMP, Bioware has been very open minded about players rejoining a game after they were in the fade. Hell, Bioware openly accepted this on ME3MP too. While Heartbreaker was being tested in Beta, devs were suggesting to testers to rejoin between zones, they considered it "fair play" and "nothing wrong with it", a feature if you will.
The truth is, NOBODY had a problem with that until there was a challenge that gave an inordinate amount of points for the leaderboard. Now people are panicking about people completing that challenge...
Bioware haven't made their position known on the subject, but I think it's pretty easy to guess where they stand. If you had to make a choice between removing a vital "feature" with all the work it requires to do so OR hope people just wake up and complete the damn challenge already to get back to their original "spot" on the leaderboard, my guess is the choice is pretty darn easy...
TL;DR
Most of the drama is about Bioware's inability to build adequate Challenge and RNG systems. Those 2 systems are responsible for like 99% of all the drama around DAMP. Yet, some members of the community are hell bent on taking it out on players...
The simple solution would simply be to remove the global leaderboard entirely. It ends most likely 95% of the drama while keeping all your hard earned progress. You could still compare yourself with your friends, but all the Epeens would mostly fall flat 
The game is actually in a much better place now than even 4 months ago, can we just enjoy it while it lasts?