90% matches are common because of the huge number of people on the site. And they seem common because those are the kinds of people you're likely to be shown.
Either that or they're usually rare and I'm just so generic I get along with everyone.
I'm sure the gay dating pool is pretty much always smaller than the straight, and beyond that the size of the pool depends a lot on the size of the city you're in— there are tons of people in NYC/Chicago/LA/SF.
I always heard that Atlanta had a huge gay scene. (But, admittedly, I'm from the South and it's probably true by definition compared to almost any other Southern city.)
Metro Atlanta and Atlanta are two different things. The metro is like Atlanta culturally, but it's not dense at all. It's 20-30 minutes to anything, unless you live in one of the bigger cities.
Either that or they're usually rare and I'm just so generic I get along with everyone.