Some alien species could be much more warlike than us.I think that if Aliens seen our planet they would stay the hell away. The first thing they would see is the space junk, they would know instantly that we were a destructive planet. They would probably be able to measure the noise, and signal pollution as well. They may be appaled when they see our planet and stay the heck away.
We are a strange society when we see someone who is weaker we overtake them with war. I think this is is why we think aliens would do the same to us. Not to mention how we treat animals for farming. But it is possible that if there were aliens that were advanced enough for interstellar travel they would be mentally evolved as well, and not have the same destrucive intentions that the earthlings have.
Then there is the theory that we are the aliens. The sumerian Tablets speak of this pretty heavily. They say that they colonized this planet to mine the gold that they needed for their home planet. Then they created a hybrid human that was kind of like themselves. Not only that, but they fell in love with the humans and bred with them. Hence you have the tales of half man half god. They created us to work in the gold mines. Long story short here we are today. I dont know if any of that is true but the sumerian tablets are an interesting and fun read for sure.