far too common, in my personal opinion. At the risk of re-igniting gender wars, it's a very masculine thing. There's an s-f story from a long time ago, probably the 1950's, in which a human manned spacecraft off in some other part of this galaxy makes First Contact with an alien species, and the underlying presumption with the humans is kill or be killed. We never really get to see the aliens and how they think, but to the humans it is utterly impossible that the aliens aren't thinking the same way.
Our war-making predilections may well be the end of us. Look at the insistence at high levels of government that our military be equipped to be able to fight two or three major wars at once, to the total exclusion of consideration of other ways to spend our money.
Also, many otherwise good science-fiction movies have that same theme. "Independence Day", "War of the Worlds", and so on. We are all guilty on a personal level of thinking that others will behave or think as we do, and when our primary thinking is aggressive, I see no good end.