If labels didn't matter then people with autism would get an easier time in life. In autism there isn't a dumb and dumber person, some autistic people are as perceptive and intelligent as a neurotypical person, if not excessively more. Are you saying a person with this condition should not express who they are through their label? Labeling things is not bad but by rejecting the label usually it means you reject the idea of it like an extra repressed homosexual person.
People with mental illness usually struggle with sexuality. Hypersexuality is a thing. You will find that what you speak of is less about identifying with a label and more about knowing what you want and like. A person who might have mental illness struggles especially with knowing what they want and don't want. Just like a person who goes to therapy, figuring yourself out through labels is not bad or dumb. It actually is cathartic.