Think "Prime Directive". I think it would definitely make the most sense to have a non-interventionist policy when considering intergalactic relations. Anything else would be immoral from a philosophical standpoint. Think about what's happening on this Earth, and who's behind it?
John 8:44:
"Ye are of your father the devil, and the lusts of your father ye will do. He was a murderer from the beginning, and abode not in the truth, because there is no truth in him. When he speaketh a lie, he speaketh of his own, for he is a liar and the father of it."