Your last sentence is correct
'social training' can be applied to anything and anyone, so yes it is about autism and it is about mental health issues too
The most anxious of us, have a feeling of dread/fear among other things, that is often linked to how we see other people. We see other people as different, competent, able, judging us, looking at us. Its a revelation to know that actually no one is bothered by you or me, no one is looking at you or me, they're quietly getting on with their lives. To know that, to learn that lowers anxiety
Its no coicidence that anxiety in kids has gone through the roof since we developed a narrative around children that centres them all the time, that they are special and unique and different. That was done with an aim to empower and validate, what it does (in some children and some adults even) is develop this 'main character syndrome' where it can be negative in that 'Im different, I dont fit in, Im not like these people' 'no one else feels like this' or that they aggrandise and become grandiose and entitled but at the same time the pressure of thinking that you are so centred and the world revolving around you makes you think that people are focused on you all the time, that is nervewracking and frightening. Hence the increase in anxiety
The best thing we can 'train' children to understand, even if they are on the spectrum, is 'no one is looking at you, their day to day thoughts are not about you, you're just the same as everyone else, other people have these feelings and experiences and confusions and behaviours and they struggle with x, y, z'
Theres always going to be some caveats to this for people who do have signficant disabilities and differences in terms of social 'norms'. Im talking in short hand.
That in essence is social training, theres far more to it obviously Im picking on one area, theres other basic stuff like learning how to engage and be socially appropriate, but it also protects our children's MH