@OP: Great post, I enjoyed reading it and nodded my head in agreement many times. This is the only photo-related forum i am a member of, but i think, like someone else already said, that the behaviour described in the first post isn't necessarily a photographer-phenomenon, but an internet forum-phenomenon. A couple of personal observations:
About PF:
Bought my camera in nov. '11. Read and enjoyed this forum before that. It's a friendly forum, and i still enjoy it, but i don't read it as much anymore, i usually just look at pics people are posting in the lens club-threads, perhaps because i'm a bit tired of people being depressive about life, the universe an everything, or perhaps because pictures are nicer to look at then text, but yes - even though i haven't been here for so long, i think there is a reason the OP made this post, and i think i can kinda feel it too.
About Pentax:
I was, after reading a few threads about it, prepared to be mocked and harassed, to some extent, by users of 'the other' brands. Here are a few of the things i've heard from other photographers so far:
-Is that one of those pancakes? Looks really nice( About my M 50 1.7)
-You're the only Pentax-user here, i think. Go out there and take the best pictures of us all!( Said by a Nikon-shooter for a newspaper at a concert)
-Guys, why are you sitting here discussing equipment when you can be out there shooting great pictures?(Said by Canon-shooter at same concert)
-Really? I like that about my D800 too! ( Discussing TAv-mode)
Not received any negative remarks yet!