It is his opinion, and sincerely I don't find 'odd' to post publicly a list of the signature campaign spammers (a personal list, this is obvious...).
As long as someone makes a public ignore list that isn't blown out of proportion (an example of this would be, ignoring everyone with a sig ad) and blocks visible spammers I think it would be beneficial as well. Since it would be a reasonable ignore list, I think quite a few people would use it, which in turn would encourage the signature campaign manager to kick that user out of their campaign. Nobody seeing their signature ad = wasted money for the signature campaign.
