I think it's a correct (or at least valid) reading that Hermes was, in some way, not neurotypical or mentally healthy. He was fundamentally not thinking in the same ways as everyone else around him. I don't know what, if anything, I'd diagnose him with (a lot of people say depression, I don't think so), but I feel like modern Earth would find ways to help him cope with that and figure himself out.

...but he wasn't here with us, he was in Amaurot, a civilization that values conformity to an insane degree and isn't very good at grasping actual problems or alternative thoughts. I can't imagine that's a civilization with a terribly strong concept of mental health, so I'm not surprised at all that he wouldn't be inclined to share the feelings he knows aren't common. There's probably nowhere safe and understanding to even talk about it, and even if there is, I don't see Amaurot being a place that would treat someone well when they learn they're getting psychiatric help.