Of course, modern gay males - think Milo - are obsessed with body image because youth and beauty is what gets you endless ‘sex’. Get fat (unless you're a chubby-chaser) or grow old and you die of loneliness. It's why you see so many of them in gyms and the old bathhouses. You touch upon a point that I do not believe is well understood by most people. "Gayness" comes in a variety of flavors, and there is not a single "gay" fetish.
There are those that prefer fat people, there are those that prefer old people, the vast majority of them prefer young boys, (these are known as "Chicken Hawks" in their own parlance) Some want to be dominated, some want to dominate, some want to dress as women, and some want to dress as Nazis.
The differences are so complicated that years ago they had worked out a system so that people cruising for a partner could recognize like minded people instead of wasting time with someone of a different fetish.
I would disagree about fat and old people - my experience with gay men is that they hate and despise obesity and older men. Honestly, they are sick people!
Yes, I can still remember the clones of the Village and their handkerchiefs which told which sexual fetish they enjoyed. I remember when they also had large, short haired male dogs who were ‘unfixed’ shall we say. I still have not had the courage to find out what that was about. The artist, Francis Bacon, painted pictures of himself in bed with his large dog. Creepy beyond belief in a Mapplethorpe way!