I have a DS freshman at U Pitt. Consider a freshman single in Litchfield Towers C. This is a mix of upperclass and freshman, but all singles dorm with a lot of single sex all freshman floors. Litchfield is considered to be the classic freshman experience - 3 huge dorm towers smack in the center of campus on top of meal service, package/mail delivery, laundry, etc.
My (cis/hetero) kid came in like yours - knew no one, down for having a randomly assigned roommate. He put 2 housing preferences for doubles ahead of Litchfield Tower C singles but didn’t get the double/roommate - I think those are mostly filled with kids who already have found roommates. Also, my DS did housing application very late, so I was surprised he got a single, which I thought would be very competitive - apparently not?
DC likes having a single and has made friends with other kids. DC has also mentioned in passing at least one gay guy on his floor who seems to be treated like any other member of the pack - going out and drinking and partying on weekends except hooking up with gay guys and with straight men as wingmen.
I think being gay is accepted and normalized for this age group, thankfully. Kids are often out in HS and even MS now, so a gay student isn’t some kind of major surprise in college.
Pitt seems like any other big state school - welcoming to LGBTQIA and tolerating no discrimination. The website says there are gender inclusive housing options.
https://www.studentaffairs.pitt.edu/lgbtqia/housing/
Georgia Tech is a great school, and I don’t know anything about the campus gay experience there, but I would think the overall atmosphere in the South would be less accepting than Pittsburgh.
Have you done the online orientation? I was getting zero info when I asked DC Qs about housing registration, tuition payment, etc., and then I figured out that parents can do the same online orientation as kids. I forget how you register for this - maybe thru the MyPitt system? I got some answers there about the housing process and the website also has descriptions of each dorm, room types, location, pics, etc.
Also, you and your DS should absolutely go to an admitted students weekend in Pitt, do a tour or admitted students event in the area. This is how a lot of kids make friends before they get to school, and is one way of finding roommates and getting the 411 on dorms. You also will have a chance to ask parent Qs that way. My DS refused to do this - but I think it would have been useful.
FWIW, I would say let your kid make his own decision on housing. He is going to live there all year, and if he hates it, better that he own that decision instead of blame you for it or imagines he missed out on something because you wouldn’t let him try.