Looking for a word that means, "a belief in goodness and liberty toward sentient aliens." The use of "humanitarian" doesn't seem to fit due to the use of "human" in it, and I am not entirely convinced that "xenotarian" is a valid word (although it might be.)
In Buddhism it is frequently used the expression "sentient beings". Reference I think you could use the same expression.
If you want to emphasize the E.T. nature perhaps you could use the expression "Non-Earthly" as in "...toward all Non-Earthly sentient beings" I don't think there is a single word expression for this.
Freedom is the right of all sentient beings. Optimus Prime