4chan discords are bathed in drama and shitslinging. Its just highschool cliques all over again. Its the same reason they hate Reddit or Name"friends" for that matter. Nobody like Attentionseekers, Dramaqueens and Literal Whos who think they are the hottest shit, its why they escaped to an anonymous board in the first place, to have discussions where the posts stand on their own merit and not the username.

Discord is hated for the following reasons on 4chan
1) many raids and spam campaigns on the boards are organized and enacted on discord
2) the stereotype of sexual deviants and transsexuals congregating on discord
3) the website has made other forums and ingame voice chats obsolete, so they say