Because Musk said so?

My understanding is that Ver renounced his citizenship because the US, along with one other country in the world (Eritria), keeps its claws in you when you become a non-resident if you remain a citizen. His "sin" from what I can tell, was trading on US exchanges and he sought advice on how to pay any relevant taxes and complied with that advice.

Like Ver or not, it seems that this is squarely aimed at anyone who aims to attain a better tax situation by moving elsewhere. I.e. it's a shot across the bows of many on this forum.