This is the way winning or losing works:

W_ : L
1 <---

Means the fighter with the "W" gets the credit.

W_ : L
---> 1

Means the fighter with the "L" gets no credit.

Everything else is just an opinion.

Your opinion evidently is that if a smaller fighter beats a bigger fighter he gets no credit because he has to lose a couple more pounds or perhaps this only applies to Pacquiao? Well... I guess everyone is entitled to their opinion.