As a fellow spoonie-kinkster and stable part of my local kink community, I have often pondered this. I'm a bit nomadic, and have been part of a few different kink communities in the world over the years. One thing I have noticed is that kinky people are often very MH aware, no matter their cultural differences. Why is that? I'd love to hear your thoughts.
My conclusions are that the two aren't linked, at least not directly. One is not the cause of the other. I know people that need to practise their kinks to keep mentally healthy. "Endorphins are free," they tell me.
For me, I simply feel that kinksters are generally more open-minded than the average Muggle and much more in tune with their mental health. There isn't the same stigma attached.