If the ratio of disabled facilities to able-bodied facilities is n:1, then your wait time for an able-bodied facility is 1/n, but the disabled person will have to wait for 1 unit of time.
Add to that that disabled people more often have medical needs around toileting (pain, urgency, uncontrollability, catheters or ostomies full or failing), and that extra wait can turn into somebody's nightmare day. For the sake of fractionally less wait for you.
It's the same reason why you should not use disabled parking spaces, even when no other convenient parking space is available.
(This isn't a sweatshop, either, the lowest paid among them make at least $45/hour).
I don't understand the "/s." The public restrooms I encounter have either one or two stalls, and one of them is always accessible. Accessible toilets are never less than 50% of all toilets in the building. Occasionally there might be one wheelchair user in the building.
Of hundreds of buildings I've been to, I have never seen a single place where that is even close to being true. Including hospitals. Do you mean accessible? With double drop handles, Wide enough to put a wheelchair next to the seat? Accessible handbasins (low, easy to reach the taps)?
I find it very hard to believe that more than 50% are.