>Registrars don't usually care.
They do when it comes to anonymous imageboards and people sending complaints that a site contains "CP", "hate speech", etc. - you could see this first-hand during the whole "post-8chan diaspora" situation a couple of years ago, where every site was constantly scrambling to find new registrars that wouldn't immediately cave and kick them off at the first complaint of nekkid 2D lolis or users posting "nigger", even if those services claimed to support "free speech" (Epik was one of the hypocritical ones if I recall correctly)

Pic related is a screencap of a copypasta that went around at that time giving suggestions for hosts and domain registrars - things may well have changed since this was written 3 years ago, so take it with an onigiri-sized grain of salt

This is nothing new either - 4chan.net was suspended after 1 person sent an email complaint to GoDaddy (hence the move to 4chan.org), and plenty of imageboards between then and now have encountered the same obstacle. The Internet truly is Serious Business