For example in many countries you need to "register" political advertising[1]. One could say that it is perfectly reasonable not to help political opponents, but then it would be reasonable to declare your business as politically oriented.
Similarly to how even private universities in the US must uphold free-speech rights is they declare free-speech friendly.
This is not a complete solution, but it does not need to be all or nothing.
[1] in the Uk there was some conversation about Ryanair's showing pro-stay slogan on a plane behind a press conference during the Brexit campaing