It's still better to keep talking. If nothing else, then the other side can't make accusations of being shut out in violation of the principle of free speech and representation for all. Surely one of the tenets of the council. You hand them a propaganda victory.
Sad to say but there may in turn yet also be bigger fish to fry. If we faced another Cuban Missile Crisis (some might argue this is one!), how would we deal with that then? Rely solely on back channels? Those certainly helped in 1962. But the UNSC certainly proved to be a good window so the whole world could see the Soviets disingenuous and ultimately humiliated.
So just keep pouring on the war crimes evidence in NYC and watch they and their (few) allies tire.
Cooch