Because he has zero chance against 70% of the heavyweights.
If he had time to bulk up, sure. But at his current weight, even if he bloated up, he would still get rag dolled against Cain, JDS, Werdum, Hunt, etc. There is no way he would ahve fought them, because he's not stupid and he knows that he would get rag dolled.
He made that "challenge" knowing it was going to be someone at LHW already, just wanted to act like he would fight anyone.
If he had time to bulk up, sure. But at his current weight, even if he bloated up, he would still get rag dolled against Cain, JDS, Werdum, Hunt, etc. There is no way he would ahve fought them, because he's not stupid and he knows that he would get rag dolled.
He made that "challenge" knowing it was going to be someone at LHW already, just wanted to act like he would fight anyone.