I think Replyguy mutated into several copy cat personae. I blocked a bunch of them before I figured out turning off relays. Now my block list is full of influencers I like and definitely didn't block. Maybe thats what happened.

These identity thieves are only going to get better at it. The only solution I can think of is an external keystore, but then that either kicks the problem up a level or makes anonymity impractical for people with a big following.