If you were moderating a community I wanted to join, I couldn't since I don't meet your standards. That's just fine. I can find one that is a good fit or conform to your standards if I really want to contribute.

The recent blacklisting feature is neat and may be enough to fix the problem. Shared blacklists would add even more power.

It's takes a certain type of person to post an idea and KNOW it will have to be barraged. The whitelist (or shared blacklist) will empower a wider range of contributors by preventing the attack in the first place.