The original question is flawed.
Barao is the best fighter in the division, even though he may have found his kryptonite. Like most guys here said, of course he "deserves" a rematch. But there should be no instant rematches at all if the ending of the first fight was clear.
That's why I think the Anderson / Weidman rematch was a mistake. I also do not recall whether GSP did not get an instant rematch vs Serra or whether it was just because of someone's injury that he did not.
Instant rematches must only be for cases where there was a close and contested fight. TJ's annihilation of Barao means he needs to work his way up again. It's only good for him also - imagine TJ beats him again, like in the case of Silva, he would never be the same.