I mean, I feel like autism is a terrible example here, it's not just some quirky personality trait, it's a reality people live with that runs the gamut from difficult to completely debilitating. Even the more mild forms of autism cause extreme difficulty in many aspects of life. If that was curable or preventable, that'd be great.
If it turns out some pathogen or chemical made me autistic, regardless of whether or not I could be cured as an adult, I'd have certainly preferred to live the reality where I had been as a child.
I think a better reason autism is a bad example is that part of its definition is that it is a consequence of fundamental brain structure and development (differentiating it from other psychological disorders which are acquired and more malleable). These aren't things you will "undo" with some gene edits. The whole brain has developed in a different way. Short of re-growing them a new brain you aren't going to change that (assuming you wanted to).
I think scientists have believed for a while that any type of “autism cure” would need to be extremely early intervention for maximum effectiveness for exactly this reason. I remember speaking with a team that was studying detection of autism in the womb for this exact reason.
Sure, the purpose was to illustrate a slippery slope, and curing autism is meant to be more obviously good than abolishing all forms of neurodivergence but less obviously good than fixing fatal hereditary diseases.
I'm not going to claim that I know the perfect place to draw the line.