Those are both examples of employment. It's true that there are some exceptions to employment anti-discrimination laws, but they don't apply at all to how much you charge someone for health insurance.

(And not to belabor your example, but the person in the wheelchair has to actually be unable to do the job even with "reasonable accommodations" from the employer. It's not enough to say "it seems like it might be dangerous" or "we don't have ramps")