Even before BootCamp, hell, even before Apple even announced the switch to Intel, there were Windows help threads.
No, most threads start out as "ABC company has announced XYZ phone, here are the specs and features, blah blah blah" and then it turns into that once someone posts "OMG wow thats a piece of fail!!! The iPhone is sooo much better!"
I'd say there are 2 reasons for that:
1) There is no clear place to put those posts so they're not sure if they're allowed
2) They see the hostile environment towards Android created by the usual Apple fanboys and don't bother, because they don't want their thread to be overrun with trolls telling them that their phone is a piece of crap and they should've bought an iPhone.
When I say Android, I mean all other OSes, I just got lazy and didn't feel like typing out Android/Pre/WinMo7/BlackBerry, etc

I think one forum for all alternative OSes would work.