The whole point of bringing 8chan down is to make it harder for them to congregate and fracture their community. It also makes it harder for new people to be indoctrinated.

Reddit found that banning hate subreddits reduced the overall usage of hate speech on the website. Even though the most dedicated users probably moved to voat, now some clueless kid who just wants to see look at memes is much less likely to just stumble upon that content.