Discord is not specifically allied or affiliated with any of these perpetrators of mass violence is the reason why; they were the medium that these mass violence perpetrators used to keep either private diaries or communicate their ideas with others. This is not being an ally, this is the nature of a communication service. Given the constant noise on that service generated via conversations, live streams, groups, these perpetrators might not be seen by the platform owners.

Kiwi Farms went out of it's way to act as a hub and nerve center for harassing trans people; the methods: doxxing, death threats, stalking, outing their personal information, dead naming. In many cases, under the burden of this constant harassment, many killed themselves to get relief from sustained attacks against them. Those fuckers are rightfully hated and deserve to be gone, never have I seen a hive of villainy and filth quite like them. What you have stated: "KF: becomes affiliated with more petty harassers, and everyone wants them gone" is a gross understatement of their impact on vulnerable people. Eww, Kiwi Farms if you don't believe my claims.