The humans moral spectrum can be broken down into white, grey, and black.
Most honor systems fall into the white region i.e. knightly chivalry
But if you have any knowledge about U.S. prison "culture," you'll know that most convicts especially the ones in maximum security prisons follow a prisoners' "code of conduct." A prisoner who sticks to these rules is considered worthy of respect by other prisoners, he's a man, not a punk or a snitch. You could says that the prisoners' code of conduct falls into the grey region of human morality. It's very brutal and harsh in many areas. Regardless, most convicts view it as a system of honor, loyalty etc.
I think Predator honor is comparable to this sort of "grey" honor.