The market is willing to provide car service to people in wheelchairs, for a particular price. A lot of people in wheelchairs can't afford that price. The law is trying to create a subsidy.

In principle the people who want the subsidy should be the ones paying for it. If you think subsidizing this is a good idea then you give your money to a charity, they use the money to subsidize the service, and then the market provides the service because somebody is paying for it.

You can also decide you don't want to be a libertarian and instead you want the government to subsidize the service out of tax revenue. Libertarians don't like this, because now you're taking money from the people who didn't agree to subsidize it without their consent. But also, politicians don't like this, because it's spending tax money and they'd prefer to spend that on their cronies in some government-adjacent industry.

So what politicians do instead is pass it as an unfunded mandate on whatever industry. This is still a tax, but now it's not a tax on e.g. rich people, it's a tax on other ride sharing customers and drivers. Who tend not to be rich people, because rich people have their own cars or private limousines or planes. Then we get a covert tax on the poor so that the overt tax money can go to defense contractors and other politically-connected corporations. It's at this point that you start to wonder if the libertarians might have been onto something.