
You’re asking under the pretense of you’re making a serious inquiry of why are white peoples heads shaped in a way that resembles a Lego head. That is eugenics, researching the biological difference of race and color. You can use it for bad or good, like for genocide or cancer research
Instead of just constantly not doing what I said, just please look up eugenics. The methodologies, the reasoning, the solutions, the goals etc. then you will see why making a joke about the shape of a white guys head is no more eugenics than a joke that references a black guy being darkskin