I don't know but you're right.
I suspect it has something to do with the pointy bits.
That's not the way you play with Lego!
Because it is hard and the little sharp points stick into your foot that is full of nerves
It is a fault of our species,.....we SHOULD be able to interlock,....but we CANNOT,....thus those 6 bumps per LEGO block,....hurt!! Damn genetics!