Chris and politics is always an unwary trap for people. Chris was mostly anti-gay because of Stewie from Family Guy. Chris was never "pro-Bush", he just said he'd write him a letter as a retarded threat that the PRESIDENT is going to get involved over trolls. Same reason he wants Biden to pardon him for a crime he hasn't been convicted on; he just views the president as someone like God that can just make things happen.
You have to remember, Bob isn't the type of Trump conservative people believe. Pointing to a really poignant thing was his belief in the UN, and that there should be a UN to arbitrate the world's problems. Bob seemed like the type of Virginia republican that would just go along with the standard quo, and not rock the boat. Honestly, I could see him voting for Hillary over "crazy Trump" because America needs a tried and true politician, rather than rabidly supporting Trump.
Then again, Chris hated Trump because he watched a Simpson's episode.
Chris always seemed way too focused on the gays for it to be just something he picked up on not to like. I can't imagine his parents talking about gay stuff around town, however, at the same time, Barb was pretty forceful about not letting him go out in Tomgirl stuff before relenting.
I think it's mostly Chris seeing more gay stuff online, and liking women better, having grown up in a time where you saw hot women in advertising all the time and rarely any, what Chris would consider, "Gay stuff".