The Predator acts like, well, a
hunter. It has too much humanism in it. Plus, it gets more human-like when people start projecting human values onto it like names, honor, warrior codes, trophies, etc.
Sure, some of the aliens' behavior resembles that of terrestrial insects, but we really can't get into the mind of insects, can we? The preddies are pretty much easy to figure out, but the aliens have bizarre behavior patterns and look less anthropomorphic than the preds do. There is so much about the alien that is (literally) otherworldly.