First, this is not a "us vs. them" thread of any sort, as I tried to make very clear in the OP.
Second, as to your question about why I "evangelize," well why does anyone? Why do you talk about why you think a particular movie is good or tell a friend that they should check out a game? It is because as human beings we generally like sharing things we enjoy with others and talking about them. Isn't that, after all, the entire point of a message board forum?
What I dont' understand is why you and others have to be all defensive about it. If someone is talking about how cool a game is, you don't feel the need to jump in and go "I don't know why people can't just leave me alone and stop talking about this game" or "I'm perfectly happy with the games I'm playing, thanks!" This is about the specific features of the PC platform and what they offer to gamers and why they should be valued. It, like any other discussion of something that is valued, is not mutually exclusive of valuing other thing things.