The whole point is calling them “mental health problems” infers there is something systematically wrong with them as opposed to the obvious result of putting men in modern society.
Mental health issues existing in the past does not mean they are not mental health issues. Besides, most men were neither alcoholics, depressed nor lonely.
Loneliness in particular is neither specifically masculine (like, is not at all specifically masculine, neither in history nor now). Nor is there a reason to believe was more or equal amount of it in the past ... when men were part of in person group pretty much regardless of what they were doing.