No individual user is the cause--let alone your look alikes. I don't think they infringe on any real and currently held copyrights. The real problem that we're trying to address is people actually ripping off others' works just to make a quick buck on our site. We respect our artists and don't want their work being stolen.
Another problem is people posting literally hundreds of ... well ... mediocre works, and then redirecting traffic there under false pretenses (lying on message boards, using click services). We certainly don't support that, and don't think that they would without the money bringing out the worst in them.
In response to an earlier post--yes, we do make (some...) money from advertising, and our site is 100% user contributed. We do provide our users with a lot of benefits, though. We host your files and make it easy for you to share it with your friends, peers, and employers, and get feedback. We're going to make the site look nicer, easier to navigate, and easier to leave feedback in the near future. More importantly, we'll be offering ways for people to find work through our site, and we have a very nice Flash portfolio that you can embed in your personal webpages. All in all, we still hope to be the #1 CG portal on the net, even without paying our users.