I don't think there is a good answer to this issue. But I get a lot a spam in my e-mail mailbox and manage to delete most of it unopened.
I notice that the latest "user" is MasterBee who is a "disigner" (sic). Well, I won't be opening his messages in a hurry (having looked at his profile). Instead, I will ignore it and wait for an admin to delete the message.
Eventual deletion of the user would be good too, but not urgent.
The only thing that would stop all spam is for the group to be completely moderated; on some Yahoo groups I belong to, messages sometimes sit there (invisibly) for half a day because the admins aren't logged in. I prefer to see ttwebsite messages promptly, and not open the suspicious ones.