I would prefer it if people didn't spread their germs when they know they're sick. I try to keep my germs to myself, but that's usually easy, since I'm able to wfh and don't generally have a pressing need to go out when I'm ill. If I did have to go out, I probably wouldn't wear a mask, though, because it's hard enough to breathe with a mask on when I'm not already ill.
More to the point, I don't see how any government can mandate that people wear masks when they're sick, unless the law is that you have to wear a mask anytime you're in public (and that's just insane). How would anyone know for certain that someone was not 'masking up' while ill? Would you report them somehow? Who would enforce it? It's just not feasible, even if you accept that it's the government's business (which is isn't).