I think it would be better to remove the incentives of the copy/paste spammers and/or provide incentives not to spam (this way).
One suggestion I can remember came from a member was to disable topic bumping for the comments from users who are not at least a member.
That is one option, although I don't think it would address the copy/paste spammers (it might address the "bump spammers").
Again, it is the
incentives that need to be removed, not
abilities/permissions.