If I'm understanding you right, the idea is that some harms, physical ones, are fair game for the law to cover, but other harms (mental ones) or a collection of boundary cases are less (if at all) within the purview of legislation.

I think there's a good conversation to be had as to what in particular makes physical harms so special as compared to others, and how existing law in every country (including the US) can constitutionally include some non-physical harms within its legislation (such as laws against sending threatening letters, or child pornography law, or fraud).

Would lacking spirituality or belief in a higher existence make you mentally healthy or unhealthy?

I agree, the sliding scale only strengthens whomever is in power. In Florida, the baker act is used like this.