"Can you help me understand a situation where a hidden disability affects a person's choice of wardrobe (causing them to wear a bowtie and braces when most people don't wear them), but doesn't reflect their judgement or decision-making skills? There's probably an obvious situation, but I'm genuinely not coming up with it."
Autism spectrum disorders, for one. Could be a world-expert in, say, games theory or particle physics, and not have a clue what was appropriate to wear when interviewing with someone of a specific social class (and their inherent expectations) for a specific role with a specific organization in a specific part of the world - or any idea that it would matter.
And then, outside of disabilities, there's culture/ethnicity. And class. Etc.
Bottom line is that you're hiring expertise, not fashion sense. Unless you are hiring for a customer-facing role where your organization is trying to project a specific image.