They may be incapable of seeing it "our" way.
And why should they?
Given that I have argued (elsewhere) that our own treatment of species that we consider inferior is rationally unjustifiable and that we would be hypocrites to expect anything different from alien visitors it would be silly of me to disagree with you.
There may be alien psychological reasons why they might want to subjugate us, quite apart from any question of resources. Maybe their evolution led to their adoption of a hierarchical system where those higher up are responsible for running the lives of those beneath them. This might make them think that taking control of us is the moral thing to do.
For reasons that may be wholly unjustified I think most assume that technological advancement and increasing moral enlightenment go hand in hand.
But you are quite right to point out that alien morality may take a very different path.
But it is all ifs, buts and maybes.