Not really understanding your answer in how you are making a point.
You are also equating how humans think and act to how aliens should think and act, especially by using the word 'manners'. I have a society that uses 'please and thankyou' as a manner thing, and then their are other human cultures that have to learn that when they come to my country. What makes us right over them? Maybe you think humans are better than every other race and animal in the whole universe, but that doesn't make it true and it doesn't make it right.
Maybe aliens are thinking what a big disaster we humans are and should never existed in the first place.
But all in all, isn't it just a wasted effort of emotion to concentrate on them, when we don't know anything for a fact in relation to them. Why not just put that energy into problems that we know exist and work on them?