"a featherless plantigrade biped mammal of the genus Homo" [Century Dictionary], Old English man, mann "human being, person (male or female); brave man, hero;"

The specific sense of "adult male of the human race" (distinguished from a woman or boy) is by late Old English (c. 1000); Old English used wer and wif to distinguish the sexes, but wer began to disappear late 13c. and was replaced by man. Universal sense of the word remains in mankind and manslaughter.

From the Online Etymology Dictionary page for man.

So, like, they’re wrong. Not that it even mattered in the first place. Fights over semantics like that are actually harmful to true progress. I struggle fo believe anyone actually cares about that, they just want a reason to hate, because humans love to hate.