It’s actually accurate. Broken clock, y’know.
We refuse that an All-American hero could be a heterosexual, white male. Who is good, kind, honest, popular and super-strong etc. He’s essentially The Man in human/alien form. Not only do people fail to respect the masculine anymore, but we actively feel pressure to mock him or call the dude who can shoot frickin’ laser beams out of his eyes as unrealistic – not because he’s bulletproof or went from leaping small distances to flying, but because he is a GOOD, POWERFUL WHITE MAN.
The notion of a Good Powerful White Man is the alien here.
There’s the reason Lex Luthor hates him too, it doesn’t get airtime anymore.
He is the reminder that humans are not equal. Some will always be smarter, stronger or better looking. Or just, all-around better people, that’s right – Superman is a better man, than actual human men. Depowered, he would still remain a good person. His power doesn’t corrupt him because he makes the choice to be good. That’s why people can’t stand him, he shows up modern character flaws – namely, most people in this century don’t have any.
Basically, messed-up Millennials see him as that Aryan Hitler mould, since he’s naturally an Ubermensch despite how he was used in Allied propaganda. And he isn’t even blonde.