With Lemmy, we have seen huge numbers of bots at times but most large Lemmy instances have registration applications turned on. As in you apply to join an instance instead of just being able to make an account.

By default this means waiting for manual approval of your account, but many instances set up automated approval behind the scenes.

This function means many spam bots are averted before the public sees them, and also spammers avoid instances with registration applications.

I mention this because Kbin, or at least Kbin.social, doesn’t appear to have registration applications which makes it a prime target for spam.

Also Lemmy has coordination between dozens of instance admins sharing details of spammers. I.e. a lot of hard work behind the scenes. I’d guess the lack of moderation at the admin level also accounts for part of the issue on kbin.

(A lot of Lemmy spam also comes via federation from Kbin.social, so much that many instances block high spam communities on Kbin and some block Kbin completely).