It's a little of that but it's also because culture usually reflects exaggerated differences between the sexes. Culture isn't this separate entity acting upon us, we are in a feedback loop with it, we create it so we can't fully separate culture from nature. Yes, men get killed more but by other men. They tend to be riskier, more competitive, more aggressive, etc. Note that NONE of these words imply "men=bad" although many types of feminists will tell you that (they're wrong IMO), clearly aggression in males has an evolutionary advantage. Just what it is. Studies upon studies demonstrate this.

Now, can we live in a more civilized manner in the modern world where men get more compassion and they commit less crime? Yes, we can do that while ALSO acknowledging that genetic differences exist.