South Ossetia is not and has never been a recognized country. This is still a diplomatically-recognized part of Georgia we are talking about.
So let's imagine that the Mexican Army sent 'peacekeepers' into Southern California. Would you ask the 'Southern Californians' whether they approved of this, or would you ask the Americans?
As long as they were aiding Confederate seperatists, it wouldn't bother me.
Which part of that would require or entail giving them U.S. passports and stationing U.S. soldiers there?
That is something often overlooked in discussions of this situation - Georgia attacked Russian troops in Georgia, not in Russia or elsewhere but in Georgia.