People take drugs recreationally, but that doesn’t always translate into worse health outcomes. The term “substance abuse” is also unnecessarily judgmental in this case because it assumes lack of self-control. Someone can be in control and take drugs, and not worsen their physical or mental health. But a growing fetus will be impacted by whatever drugs are taken by its bearer, either mother or surrogate (we don’t know). So I get the point you’re making, but the law you’re citing doesn’t work as a good enough counter example to my point (at least I don’t think so) because this law isn’t about the individual’s health, but about the fetal health.

I think a better counter example to my “there’s no law which requires health” statement are anti-smoking stipulations against people born after a certain year. So essentially, anti-smoking laws do make an assumption that you’ll get unhealthy if you smoke, and therefore you shouldn’t. However, policymakers can say that you’re not obligated to healthcare as a right because there are different laws which are already protecting your health, and they would be right in their own place.

The reason I think universal healthcare makes policy sense is that health outcomes are dependent on randomness. Someone can have bad genetics, or be born into environmental conditions which impact their health, both things which are random and not under personal control. I don’t think it’s a good idea to leave national productivity up to randomness, especially when environmental factors like pollution can have deterministic effects, like worsening population-level health outcomes. For a country as big as the US, healthcare should be left to the states to decide, but most states will find that providing healthcare will result in better productivity (I think).

> because this law isn’t about the individual’s health, but about the fetal health.

this is just twisting definitions. The law can't remove the fetus if the person carrying it is abusing drugs (or whatever), so the law applies to the person carrying the fetus. That is a "law that says you can't be unhealthy" and the reason is "because it hurts the fetus".

we also put people that have pica disorder into mental hospitals, because they eat things that are not healthy.

This is a law that says you can’t harm another person, not necessarily that you can’t be unhealthy.