Sure trolling is sometimes just being an asshat. But it's also a way of creating diversity. An attempt to deprogram members of a cargo cult. It can be fighting group think and ideological tribalism. I've come to think about trolling as often being an expression of a desire to write - it's very essence is writing something that didn't need to be written and doing so in a way that's tailored to one's audience. Just as sarcasm can be a low form of wit, trolling can be a low form of literature.
If everyone who trolled the Usenet or a mailing list or an online forum was condemned for it, who would be left and would anyone want to read what they had to say.
Xah Lee is a person whose particular genius doesn't fit well into a prefabricated category. But his website expresses a genuine desire to help others by sharing what he knows - and what he knows, he knows really well. There but for the grace of god, go I.