/r/The_Donald has effectively been archived and marked read-only. There's no or little activity - the link you posted was an exception - all users have moved over to a third party site.

While one could argue that Reddit should have removed the subreddit sooner, I'm not sure that would have done them any favors (see Streisand Effect.)

They opted to strangle the community slowly, hoping it would dissipate. But it just moves elsewhere, like it always does.