Was the Predator evil for the sake of being evil or did he feel he was doing the right thing?

Subjective in the sense of morality. The predators come from a planet where hunting is their way of life. With this in mind you must then ask if it's okay to kill another sentient despite all of this. I would say that their actions are unjust because of the fact that despite their way of living they travel to planets and completely disregard the laws those inhabitants have towards harming one another. I guess you could put it in the mind-frame of big game hunting and poaching.

Subjective in that most people in the audience won't agree on what is evil let alone assume they know what a predator subjectively recognizes them selves as evil or not. Be that as it may most people don't believe their evil in terms of the choices they make. A sociopath doesn't believe theirs anything wrong with cheating lying or hurting other people to get ahead and don't think its evil to do what needs to be done to get ahead in life regardless if it hurts others or not. I'll admit I don't know the motives of your question but given there is such much trolling on the internet and the way your questions are phrased it really sounds like your baiting for a does evil exist debate more then anything specific to the predators actions.