You've hit a pet peeve of mine:

The key feature of witch hunts as a concept is the non-existence of witches. If you have a hunt for something that certainly exists (Soviet spies infiltrating US institutions come to mind) it definitively isn't a witch-hunt.

For my part, I'm going to keep downvoting comments that say nothing in the most bland way imaginable, and flagging anyone who posts "I put your question into ChatGPT; here's what it says" (in contexts other than discussions of chat bots).

On the other hand if your human comment is indistinguishable from a bot comment, maybe it’s ok to be kicked out?

Related: Reverse Turing Test: https://en.wikipedia.org/wiki/Reverse_Turing_test

This is what it's like on Reddit. Many of the popular and smaller subreddits won't let you participate unless you already have gained a certain amount of karma, but you can't gain karma without participation.

New users can't participate unless they go out of their way to find something they might not be interested in and comment until they have enough points to participate elsewhere.