We may not need an assault weapon, but there is the 2nd Amendment component, and creeping gun control that goes with limiting what a gun owner can have.
When are they doing away with Hammers, Knives, ball bats, fence post, shoelaces all have been used as killing weapons. Not to mention poisons.
It's also a diversion from what all of this homicidal maniacs have in common. From the little information that trickles to us online, it seems that they've all been prescribed mind-altering pharmaceuticals, which might explain the dead look in their eyes and their blurring of fantasy and reality.