"Don't encourage them" is a standard admonishment given to people in a group IRL when one member is acting out. And it's demonstrably impossible for moderators to find and remove 100% of content in violation of policy.

It pushes added responsibility on the upvoters to think before they upvote, but perhaps that is a fair request to make of forum participants.

(And taking off my "community moderator" hat and putting on my "sysadmin" hat---both dusty from lack of use---using sock-puppets or a like-minded collective to brigate-upvote content so that it is visible before it gets banhammered is a known attack vector against the infrastructure itself, and mitigating that attack vector via added penalty for the supporting accounts doesn't seem unreasonable).