When you say "no fats, no fems", you refer to a human's physique. It's like what you wrote. I want a sports car. I want leather seats. But when you see "No Blacks, no Asians", the person dismisses an ENTIRE race which to me is Racism. If he indicates his preferences "Not into Blacks with big dicks" or "Not into Asians with small dicks", that I understand. OK, they're stereotypes but at least the person doesn't reject an entire race.
If the person wrote "No Jews" (and let's say you're Jewish), would you accuse him of being anti-Semitic? Or would you think it's just his "preference"?
I bet you're white (and I might be wrong) because you dismissively think "their race preferences are no more or less offensive than Cormac's "no fats, no fems, etc." which is comparing orange with apple. A person who hasn't experienced racism would not write something like that. You might think there is nothing essentially wrong with the line "No Blacks, No Asians" but to Blacks and Asians, it's quite offensive. And racist. Some gay men think it's OK to use it and hide their racist views behind the "Oh it's just a preference. I have Black and Asian friends" blanket. It's like saying, Yeah I have minorities in my team but I only promote Caucasians.
And Yes, the dating apps DO represent gay men in a way, including you.