The way I see things, it doesn’t much matter where these accounts come from. If they disrupt the community without providing value, they gotta be removed.
Now there is a bit of nuance in that human users can potentially become helpful members of a community whereas automated users probably won’t. So if you see someone flailing around and think they have potential, you might want to hold off on kicking them out. Maybe make allowances for factors such as non-English speaker or immaturity that a little time might straighten out. But if there’s no sign of progress, it doesn’t matter if the account was created by a machine or a human.
I suspect it’s possible to identify automated accounts from looking at account details. You might get some mileage adding domains to blocked email domains under Login settings. (Just, you know, make sure it’s a domain that won’t be used by legitimate users.) Blocking IPs (/admin/logs/screened_ip_addresses) might also help. Still, I find it’s better to let people show me who they are and then take action. Preemptively blocking stuff isn’t as helpful as you might imagine.