Generally companies are welcome to choose to who to provide service to, as long as it's not discriminating against a protected class, or ruled as anticompetitive (which is a very high bar in recent case law; even if the same 1890s-era laws are still on the books).

I don't think a correct remedy is to require companies to provide services even if they want to. A simple example: you drop a client because their asks / ways-of-working / etc is more headache and costs than it's worth. I've done that before, multiple times, in my freelancing life.