So tell me, who is mentally ill? it's subjective.
What makes you, me, or anybody else, more "healthy" than others? lolol..
There is a range, and like anything else, stuff like counseling can be abused, especially when drugs are involved. I've worked with the mentally ill in the past, and there's a broad spectrum of what is defined under that umbrella. Some of them are downright scary - severe bipolar cases can be completely unsafe to be around if they are violence-prone. But then there are some people who have depression and just have a hard time getting out of bed, but aren't a physical threat to other people on a regular basis like other types of mental illness are.
Not all mental illness is subjective, but some is, for sure. I mean, even insomnia and perfectionism fit in the metal illness category, and that can be fairly subjective because maybe you're just having a hard time sleeping for the past few weeks, or maybe you haven't slept in 20 years. But if you think
all of it is subjective, go do some volunteer work at a local hospital, ward, or retirement home and see for yourself what is real & what isn't.