Banning/deleting users won’t “end the assault”. If you notice, each spam account only gets off a post or two. On rare occasions one might go rapid fire and get off five new OPs…but these are all new accounts.
As cporter pointed just a few posts ago, the issue is basically the lack of tools in the forum structure. Account creation is free, and the only verification step is receiving an email.
There’s really nothing that can be done to prevent it until we switch to another forum or new tools are added to this one. Or just disable new account creation entirely. But I doubt we want to do that.