I have banned multiple of those accounts for DM spam. Banned a new one just now.

I'm not sure this is a bot. I suspect it might be a real person who doesn’t realize how they're coming across. Initially, I thought it might be a strategy to get attention, but if that were the case, I’d be surprised by their persistence with a strategy that isn’t very effective.

I suppose it is kind of effective if we are making posts about them... Hmm...

I prefer not making too many assumptions other than to assume no malice. But of course the DM spam will not be tolerated.