Urzael, yes. The many thousands of other angels ? I find it hard to believe they all went missing just to search for him and nobody found it suspicious. But let’s assume the Council, still trusting Malthael, thought it was ok if his host did whatever it wanted.
Tyrael didn’t need to tear off his wings to go back to Sanctuary. He did it as an example to his kind, that man and angels are tied together no matter what the Council says. This act alone was against the laws of Heaven but it didn’t prevent Tyrael to come back as a Council member.
Moreover, a rogue angel could have fled right before they closed the door. Or he didn’t come back from an outpost in Pandemonium, which could be interpreted has being killed or at least MIA. The Council wouldn’t have a clue it’s a deserter, especially if there’s some commotion in the Heavens.
Not to mention the angels that may still live hidden in Sanctuary long before that.