How do libertarians (and free speech advocates) deal with the issue of social media de-platforming being in contradiction with private company control?

I hear about the case of the wedding cake maker who refused service to the gay couple. People said ‘private companies should have the freedom to refuse service to anyone’. Social media private companies deplatform and remove right wing or conservative voices. People say ‘they shouldn’t be allowed to de-platform.’ How is this contradiction resolved […]