Sexism means discrimination on the basis of sex. Stating the next SC justice isn't allowed to be a man is sexism. That is undeniably a correct statement.
Now, you believe sexism against men is justified. You should own that and just admit you're deeply sexist, you're engaging in misandry and female supremacy and you're happy about that. Don't try and alter the English language to pretend that isn't your position: own it.
But I don't know if you will be able to, as you're not only distorting the language around the word sexism. Biden isn't "pointing out" a lack of representation. He isn't a passive observer merely remarking on a phenomenon. He's stated very clearly that he should be the guy to pick and he will not pick a man or a white person under any circumstances. That's not "pointing out" - it's active sexual discrimination against men and whites.
Again, own it if you like. Say you're a sexist and you think it's justified, you wish it weren't illegal because men should lose by default. But don't try and claim that statements like "men are better than women" isn't sexism.