Peter Thiel, one of the top GOP funders (and likely reason for JD Vance pick) is openly gay. Of course for him the reasoning is simple: he has a lot of money and wants policies that favor people with a lot of money. I've known a number of rich people in my life, and many (not all) have bought into a sort of wealthy identity, thinking of wealthy people as superior to non-wealthy people, and that the ideal social structure is a rigid hierarchy where the "deserving" are rewarded with luxuries and the "inferior" working class deserves a life of cheap labor. Psychological incentives strongly encourage this, because otherwise these people would have to believe they are getting more than they deserve, and that they themselves are too weakened by a life of luxury to be as supportive of the as fortunate than they should be. Accordingly, this identity can be more powerful than something like gay identity.