Suppose I want to ask for specific legal advice, and can format it as a yes/no question. Also assume that the no-RSLA policy of Law SE is not enforced, only actual laws on unlicensed practice of law. If I post my question, and then I post two answers, one saying "yes" and the other saying "no", and the community "answers" my question by upvoting the right one and downvoting the wrong one, are voters guilty of unlicensed practice of law, assuming they would be if they had answered in the traditional way?
No. In order to practice law, one must establish an attorney-client relationship.
Participation in Internet forums absolutely does not establish an attorney-client relationship.
Everyone involved in law spends a disproportionate amount of time disclaiming this, so nobody inside the field will be confused on this point. I believe this is also directly stated in the Terms of Service.
And as Jen notes, upvoting/downvoting is not even agreeing with the legal validity of the answer. Take the tour or read help pages for what voting means. It's perfectly conceivable for a psychic who knows how to sway people could write a better voted answer than three lawyers.