As a bottom, I'd simply say there's some equivocation going on here.
Guys/tops always say they like a "tight" ass, but that's the opposite of what they really mean, in my opinion. I've topped, and if a guy's ass is TOO tight, it hurts my dick because it squeezes too hard. In addition, if he's THAT tight, the bottom typically cries all the time and demands the top slow down, and is otherwise annoying as f*ck and only focused on his precious little needs. On the other end, I have stuck it in and not really felt anything because he was a gaping hole.
When I bottom, guys respond most when I'm the loosest. They tend to say something like, "that's a tight ass" or "nice tight ass," but in reality I'm in doggie position knowing that my hole just relaxed and "got loose."
So I humbly submit that when guys say they like a "tight" ass, they mean a warm, wet hole that and take their dick anyway, isn't too loose, but isn't tight. It should literally feel like a pussy, but just a little tighter than a pussy. A truly tight ass physically assaults and hurts a dick. I know, I've topped and I'm hung.