This is going to push people away, including long time users of the site.
It has already done that. Just look at the drop-off in usage since this became an issue. The numbers here were on a gentle downward trend anyway but over the last 18 months or so it has had a serious effect.
Is this a bandwidth issue? A DB issue? An issue with an overwhelming number of bots swamping the site?
Mostly the last of these. Any large-scale, dynamic site will have been suffering the same. Every kiddie and his dog needs "training material" for their shiny new stochastic parrot. There is no silver bullet and techniques and success rates vary depending on the detail of the site under bombardment.
What I might suggest is to make use of the fact that the Monastery has multiple domains. Keep .org open and free and let the bots have at it (within reason). Put .com and net on another front-end host and there require a login. That way when the botalanche takes down host1 the genuiune users can still get in on host2. It's not great but it would be better than the status quo. Of course, if the bot activity is killing the back-end as well, then that's another matter.
