This seems entirely non-sequitur. We don't have condom mandates because there is no practical way to enforce them. We don't have mandates that you need to wear a mask in your bedroom, either. If we allowed sex in stores and restaurants and didn't have condom mandates for people having sex in stores and restaurants, you'd have a point, but we don't allow sex in public. Porn performers don't have condom mandates, but they do have a mandate requiring them to show proof of a recent negative test before they're allowed to perform. I suspect many people you think are level-headed would be entirely supportive of legally mandated condom usage for non-cohabitating partners if there was any remotely realistic way to do it.
And, of course, we do have an absolute shit ton of mandated vaccines, so mandating one for Covid is not at all novel. It's even already a condition of federal employment in a lot of cases. If you're serving in the state department or military or something where you need to go overseas to places where anthrax or malaria are risks, you need to get vaccinated, and that's been normal and in-bounds for half a century.