So if I don’t think he’s black in the cartoon, I’m racist, and if I wanted him to be black (played specifically by Denzel Washington) in live action, I’m racist. OK

You say this as though these two things are contradictory but they're not. Two different things can both be racist. If multiple people tell you that in a situation, you're saying racist things, when do they become credible? Everyone is racist. The key to fighting racism is accepting that.

I gave you the reason that what you said is racist. Instead of examining that, you took it personally. You can't eliminate racism in yourself if you get upset when someone says you did something racist. As a white person, I will inevitably do something racist. That's why I listen.

As a non-white person, I’m not taking instruction on anti-racism from a white person

You’re actually the first person saying that any of this is racist

For the record I’d also be down with a black Superman. Calvin Ellis, Clark Kent, Val-Zod, either way doesn’t matter. Diversity is good.