Anti-discrimination laws don't cover everything. For instance, it is generally OK to put out a casting call for a blonde male actor, and a company can refuse to hire someone in a wheelchair for a warehouse job.

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")

Well, we aren't talking about everything. Only insurance premiums.

I'm pretty sure men and women are now required to get the same rates for health insurance under ACA. How are they allowed to charge people differently based on age? Well, because there's no law against it. Age discrimination is illegal in employment and housing, but not in what you charge for insurance.

Prices for health plans on an ACA exchange can only vary based on age, family size, smoker status, and a geographical "community rating" that's designed to account for local cost of care. No other factors may affect pricing, and anyone who is willing to pay the price must be enrolled.