Master of Palettes
I don't have long enough to read the whole thread, so I'm just going to reply to the first post.
Having been here since 2009, I do agree that game development has lost a lot of its sense of community in the last few years. But I don't think this is just a problem with this one section, it's a problem with the whole of the forum. Many older members have left and haven't been replaced by enough new members. It's one of the reasons I've mostly left the Game Development section and entirely left the rest of PC and gone to deviantART. There's a lot better community over there then there is here.
As for people criticising, I honestly don't think this is a bad thing most of the time. Yes, comments that go along the lines of "This is bad because it is" obviously don't help, but most are well written constructive criticism. If someone can't take the CC of other members, and therefore improve their game with it in mind, they shouldn't be making a game. My entire game is based around the criticism I have taken, and it looks far better than it did at first.
And people holding grudges is just something that is always going to happen in this kind of community. The majority of members are young and still immature, so will tend to hold grudges against people instead of thinking it out logically. People from this section have held grudges against me, but I really haven't taken it at all seriously because I know they're just immature. A lack of good moderation at times (such as when there were no mods) also hasn't helped.
Edit: After reading the rest of the thread, I'm probably going to double the size of this post in quotes once I get back to my computer.