negative knockback resistance doesn't increase knockback taken by user

I gave a helmet and a bow -1 generic.knockback.resistance.
I tested getting hit by a skeleton and a zombie whilst having the bow in my hand and separately wearing the helmet. The knockback from the mobs was identical regardless of if I had these items in my hand or equipped.

I tried changing the operation of the attributes and amount but this made no difference.

I think negative knockback increasing knockback taken would allow for some cool situations.