Well EVERYONE did equally hate Deception and and we all agree it was just plain terrible in every respect, so I think you're not giving the hardcore fans (like me, Hehe) enough credit, as that proves we can see when something sucks even if it's part of the Mass Effect series. This is really more about how big a deal the error is or rather than whether one was made (yes I started by thinking there wasn't an error, but now I see I was wrong and I admitted it, no harm done - what does that tell you?)
And also, if you CAN give an excuse for something to make it work in a fictional universe, why not do it? It'll help you enjoy the game more. I mean every fictional universe has writing mistakes or lore inconsistencies, Star Trek is riddled with them. Point it out, express your displeasure with it, then reason it out the best you can if it really bothers you, no need to let every little one kill the series for you, or call the creators pompous idiots for it. But I didn't say BioWare didn't make a mistake, just that its a small one we can use our imagination on. Big mistakes are things more like Deception (in its entirety) and (arguably, most aspects of) Dragon Age 2, not a character saying the wrong ship class in a frantic situation or a slightly misleading text crawl.