> This is just conveniently redefining what most people mean when they talk about objective factors.

I disagree. People have complained about the increase in television channels and shows leading to a breakdown in the cohesiveness of society. Broadcast technologies (along with the related rabbit-hole and bubble effects) are definitely an aspect of "objective factors" that people talk about.

> People tend to think of issues that impact mental health as somehow less objective, because mental health is itself subjective.

Personal mental health is subjective in much the same way that personal ability to find a place to sleep (from couch surfing to buying a mansion) is subjective (and becoming harder due to demographics and new construction deficits).

Social mental health (sociology) is an objectively measurable criterion. As indicated by the link in my edit to the post you are responding to.