I feel bad for you, I mean my mental health issues are such a huge part of my life that I know if someone didn't try to understand or at the very least be supportive, I couldn't share my life with them.

It's very small minded to think that disorders/ illnesses don't exist because some diagnostic manual didn't make it official until relatively recently. Actually, it would be a toss up between walking away due to utter lack of support or walking away due to their utter stupidity.