1. Balding (there are rare caveots to this though).
2. Overweight (my threshold is over ~20% bodyfat).
3. Small (note this does not equate to short, just a small build in general).
I really don't like having the standards I do on a physical level, it's frustrating. That's not to say I don't see guys that meet them. I actually see plenty of them. I'd say around 10% of the guys I see I am like "oh yes, yes please" on a given day in town. Granted, the true "holy crap you are exactly my type" is very very rare. I have tried multiple times to ignore them or lower them, and it just doesn't work.
As far as gay guys and balding, from what I noticed a higher percentage compared to the heteresexual population at large tends to be turned off by it, but by no means all of them. I have come across plenty of gay guys who see it as a non-concern, or even a turn on. Just for me I do not. Part of it could be that one thing I rather like and find I am universally drawn to satistically is a short forehead / low hairline. It's likely because I am the opposite of that.
I'm also just sensitive to it in general. I have been worried since high school that I'd go bald. My father went partially bald in his early 30's, and my paternal grandfather went completely bald at 18. Unfortunately, when I had part of my genome sequenced through 23andme two years ago I learned that I have a strong increased statistical odds of going bald. My hairline has receeded very slowly since my mid teens and it's something that is always on my mind in some capacity. I do not let it show, but I am self conscious about it and am very sensitive to my physical appearance. It's also a bigger deal for me because my hair is a major portion that makes me attractive to others. To lose that will absolutely send me down several notches, even more so because of my head shape. While I recognize that am solid above average in attraction, the perfectionism in me beckons it not being good enough, and not being good enough to draw in what I want. I do not let it get to me 95% of the time, and I can ignore that internal poking. Balding though; I know I could not handle that at all. I have also found that unfortunately, I need to feel attractive in order for me to enjoy someone else. That said, because I know being self-conscious is a turn off, I'd never let it known. I never divulge my insecurities with myself in this regard.
Granted, I do agree that you can make it A LOT worse by trying to hold onto it or use bad hairstyles. I also agree that there are some people that wear it well. Some though, can't. I'll be honest I do not see the appeal in patrick stewart at all. I just accept that others see it, even if I don't.