linuxmemes

Having moderated forums back in the day, I can answer to some of that motivation.

First, some people are just bullies. A sense of tribalism forms around bullies, who feel the need to act out and repeat the abuses they have endured. Hazing stems from this, too. Cruelty masked as "you should know better," advice. Given too late.

Some have a smug sense of superiority, and want to keep it that way. Less smart people means they stay king of the mountain. Others are scared their own lack of knowledge will cripple them if they don't keep the potential competition down. Insecurities drown out any sense of empathy.

Some people hate themselves so they punish others in retaliation. Like, trying to erase past cringe by making others hurt to even the score.

A few are sick of "the same fucking newbie questions again and again and again," but still hang out in newbie forums for some reason.