Yep. A lot of the spam algorithms penalize new accounts, so spammers started making them months or years in advance to sit idle. Now that’s a spam flag.
At this point, companies should just suck it up, hire (more) real human moderators, and deal with the spam manually.
The amount of spam created by computers can always outweigh the effort required to clean it up by humans. Hence enlisting computers to fight the spam before it gets posted.
This implies that these companies care enough about their users' experiences to do something "expensive" like that.