Sure. Might be hard for people to do certain manual labor jobs without access to sharp objects. I'm sure they'll figure it out.
We'll have to ban rocks next though.
It's pretty hard to stab people with rocks, especially multiple people.
Generations of Native Americans beg to differ.
The native-american generations population probably doesn't intersect with the population of teenage knife-wielding attackers in london, which is what we're talking about.
Then again, if you want to argue stone-age semantics: we can't ban anything and should just resort to continuous murder since rule-based society is too hard.
We just need to watch out for teenagers learning flint-knapping.
But pretty easy to cause blunt force trauma to the head