This is at the end of a long long line of trying to find some way to deal with one of the more unruly subreddits on the site that's been the source of loads of brigading, vote manipulation [0], and doxxing. If a community can't behave after 4 years of warnings and increasing controls at some point Reddit had to do something, this is short of just banning everyone and nuking the community which they're well within their rights to do.

[0] At one point td was basically the only thing on r/all because they found out that by upvoting everything and stickying posts to get upvoted they could spam the rest of the site.