Another reason, why we should care less when they kill each other, Sunni-Shiite, Alawite-Sunni, or whatever Intra-Islamic bigotry causes...
It is likely that Russia and China wish to control the change in Syria to assure a Russia/China friendly puppet state, excluding the Muslim Brotherhood. Said state will continue much as before, just always operating with Russian approval and permission.
Michael Bristow from the BBC wonders if the strong alliance between Russia and China might be straining as the situation in Syria worsens.
LOL, wishful thinking. Russia and China both got screwed by NATO on Libyan oil and gold, it'll NEVER happen again. Besides, five other temporary Security Council members will also veto. US involvement in Syria will have to be extra legal.