Mmm, one smart forumite once said
"We criticize the games because we love them".**
** Whoever said this, feel free to claim your authorship rights
I would say that this quote represents the attitude of a lot of posters here quite well. Of course, there are probably many of those who are completely unhappy with the direction of the series and some people, who post negative posts just to provoke reactions from hardcore fans, but I am convinced that most of the critics like something about Mass Effects, don't like something else, but this does not prevent them from wanting to play Mass Effect 3, if not for anything else, then at least to finish the trilogy and are worried about something else. Worried because they still care enough about the series. And that's a good thing.
So, I would not be too depressed about prevalence of pesimistic posts. A lot of them still come from people who hope that Mass Effect 3 will deliver and plan on buying it.
Oh, and I would like to point out one thing in your post which is partially related to your topic. A lot of discussions, especially those with some criticism of something, tend to turn into heated arguments because of some innaccuracies in the beginning. These are often caused by overgeneralizations and unwillingness of posters to go into details and address particular single problem, issue or poster. You, for example, did such thing too by saying
Sweawm wrote...
When it comes to Mass Effect 3, everyone seems to be a pessimist.
Everyone spends there time complaining about characters and everything else about Mass Effect.
Hell, even if he came with the most emotionally lifting story in the history of gaming, everyone on BSN will still be calling hate.
Next big thing that sucks about the community here is that everyone is too focused on their own opinions. I have opinions, you have opinions.
Not only I am fairly confident, that "everyone" can not be used in any of those statements, but you could get yourself into an argument fairly quickly if you said "everyone" loves or hates some character / feature / etc. So, be careful. Your intentions are good, but the roads to hell tend to be paved exactly with those.