> In free societies, governments should only be able to forcibly compel people not to do things

Well, how about "don't discriminate"?

I am not saying it is the perfect solution, but if you want to refuse a service you can always terminate your commercial venture. I do not necessarily see this a clear cut case of positive/negative right.

Similarly to how the state can compel you to get a driving license to drive. You can just give up on driving.