With no apparent sense of irony, members of the reactionary right are carrying signs stating “My Body, My Choice” at anti-mask demonstrations. This is, of course, a slogan used by abortion supporters.
I would guess that, if pressed, these people would argue that abortion is murder, and masks don’t work. The latter is demonstrably false, and the former is a philosophical position, not a scientific one, with which most Americans don’t agree.
In reality, what the sign means in this context is that I, as a real American, have the right to do whatever I want, and you, as an interloper, can go suck eggs.