If prejudice is bad full stop, even to entirely freely chosen actions, then it's wrong to criticize people for writing prejudiced comments - after all, you're being prejudiced against prejudiced comments, and being prejudiced is wrong.
(Please note that criticising nested paradoxes of tolerance expires after one use per conversation.)
I can't be prejudiced after reading their comment. Prejudice would be dismissing their comment because their nickname contained a word I assume means they're not worth listening to, as an example.
(Please note that criticising nested paradoxes of tolerance expires after one use per conversation.)