First, an obligitory rebuttal: dude, animals are no more peaceful than humans.
There is no violence or enmity in the LEGO universe until you, the builder, decide what to build with the pieces. So what if the people who design the sets had violence in mind? You have to follow them. Even more, those lances, swords, and other similar legos make better structural components than weapons -- have you ever successfully injured a lego character with one of those? It's only in your imagination.
I say, rise above the instructions. I say, build your own lego universe.