FWIW most of these "kamikaze" accounts seem to be on the lemmy.world and sh.itjust.works instances. I think lemmy.world might require an admin to manually approve new accounts -- there's a delay between application and account creation. And they explicitly state they don't allow people to create accounts using temporary email addresses.
sh.itjust.works seems to allow anonymous account creation. Still, it might not be bots/API abuse; the accounts might actually be created by hand by someone very motivated to post and delete for... some reason.
But why these two instances in particular, I wonder?
