Well, I don't think so, not without context at least.
I can think of various hypothetical subreddits that could
Check skin tone as a part of verification
Let me know if these do seem racist though:
/NakedCamouflage : members give and are given advice on using their own skin as camouflage
/ScarConcealingMakeupRecomendations : cover up scars, need makeup that matches skin tone
/RaceStratifiedPolling : sometimes you want to know how different groups feel about one question.
Idk about you but I think when I was born my skin tone was checked as a part of my verification as a citizen. I think it's okay to check skin tone, BUT I would agree that the literal definition of racism is like one or two steps from this kind of info gathering. I just don't think checking without other context is racist.
Tldr: disagree with OP's descriptions being "Literal definition of racism"