The reason people sided with the hunter
Is that the actor who portrayed him was more charismatic than all of the Mexicans put together. His character was unique, more developed, more 3-dimensional. He viciously kills them, but he also lovingly cares about his dog, which you can’t help but adore.
I understand that killing the Mexicans made him the villain. But he came across as more of an anti-hero for the above reasons. I would have liked it if he survived.