I had Absolute Virtue in play, it blocked all damage from Purphoros, and several other damage abilities, but then opp killed me by attacking.

I was playing with Najeela, blade blossom in Brawl, had white tree, Sting, barrow dagger, Storm the vault (flipped), Rythm of the wild, and a couple of treasures, Sticky fingers on Commander, and Absolute in play. Opp, made me sacrifice my commander, then attacked with Vito, Bat god, and a Dragon, Activated vitos ability, had Sanguine bond in play. Some how managed to do damage to me and kill me even thouag Absolute Virtue was in play, had all of its abilities, and there were no damage prevention blocks in play.
IS this a bug, or am I misunderstanding how Protection works?