By that logic, every single specie would be susceptible to slashing, as we are always trying to cut everything down.
I always thought those dmg weakness kinda obscure aside the always obvious weakness. Because dev can always completely reverse everything and never give any explanation for that.
It's all kinetic energy. Just depends on the area the force is being distributed. If a dagger, axe, and club all hit with the same amount of force, it's all about the denominator. Realizing that an impact is just N/mm2 (lb/in2), the smaller denominator will hit harder.
Of course, a heavier object will also have the benefit of simply having more inertia in the first place. Human arms can only accelerate so much by the time they get to the target in front of them. So even though a piercing edge of a dagger has the smallest surface area, the club has the most momentum.
The trade-off is that making a large weapon that also has a tiny striking edge can be really challenging depending on the materials. It would break (or at least dull) if the material couldn't handle it. That's why swords were basically oversized daggers in the bronze age and didn't take off until we developed furnaces hot enough to lead us into the iron age.
