Because he does them pointless little upward elbow strikes instead of making space and throwing something worth while, he was lucky Silva is not all that smart of a fighter in there last night and did not go for the body shots when it was the body shots that was hurting brown.
Hell, it could of been stopped in the first round if it was a different ref in there maybe it would of been stopped. Fact is, silva had the fight there to be won and did not captiplize of the fact Brown cannot take a body blow to save his life.