A house painter can tell his clients he will paint any color they want except for orange. This is his right. He does not have to sell his services if he does not want to.
If someone wanted a room painted orange they can simply contract with another provider.
According to these people, if the painter has a license from the State, he gave up his right to refuse service.
If the house painter's boss wants the contract and tells him to paint the house orange, he doesn't get to refuse and still keep his job. The government has no business interfering. Thus, this regulation should be rejected in its entirety.