He uses the words "slur", "bigotry and prejudice", "as inexcusable as racism", and "lacks self-awareness and empathy to the same degree as a racist".

Does that seem any more reasonable and rational than "as bad as racism"?

I could even get behind the basic idea that ad hominem attacks are always bad, except that he's already launched an ad hominem attack against what he assumes are "purple-haired Millennials with nose hoops and personal pronoun mood-rings" in the same article! I don't see how to read this as anything but "snarky insults are reprehensible when they happen to me and totally justified when I throw them at someone else."

Heh yeah fair point :-) Although even that is to some extent ad hominem; he might be being hypocritical, but that doesn't make the point itself wrong.