We cannot know the motivation of aliens. However, we can know that they evolved. The process of evolution means that whatever their version of "genes" are were

We cannot know the motivation of aliens. However, we can know that they evolved. The process of evolution means that whatever their version of "genes" are were those that were most successful at replication. Organisms composed of genes that were the most successful at replication are undoubtedly dangerous. However, in order for them to come up with technology, they must have developed some semblance of cooperation. It's unlikely for star travel to be developed and kept by only one long-lived individual (although possible) The question is how far does their cooperation extend? Even in humans, we're only really good at cooperating with close relatives or mates, and the same is even more true for other animals. So I think the point is valid. Except that I'd definitely be willing to sacrifice the entire Earth for 10 minutes of interaction with an alien being :)