Even if there is alien life, so what?
Think about this, as far as we know, there is no advanced lifeform with technologies within some lightyears around Earth because otherwise they should be easily seen, so if they are actually capable of coming over here, they must be capable of doing intergalactic travel to cross incredibly amount of distance and probably do so with relative ease, or at least compare to our current tech. So obviously being far more technologically advanced, they most assuredly will also have a far higher moral standards than us.
So it's not like we're really endangered or something. I have no idea what's with the fear with aliens, and not just alien lifeforms, the aliens who are far more intelligent and technologically advanced than us.
Make no mistake, assuming that aliens with FAR superior intellect and techs, possibly beyond our comprehension, at their disposal would have the mindset of earlier men from many centuries ago, and think mostly on terms of destroying, pillaging, and enslaving, is just stupid.