Facebook is a private company. It can’t violate the right to free speech.
When a small number of private companies hold between them a near monopoly of a market, in this case social media, it is called a cartel.
If between them they force customers out because they don’t like their opinions, it is discrimination, and a manipulation of ideas no less vicious than price manipulation.
It’s not possible to redefine the right to free speech based on one’s own opinions. Again, it’s a private company. If conservatives dislike how they’re treated by the platform, they should start their own social media company.
Actually it is perfectly possible, given that these companies have no difficulty defining what speech to ban.
What you say is similar to saying “If companiies don’t like cartels in grain prices they should start their own grain wholesale companies.” Well no, the information market should be subject to fair trade supervision like any other.
Either that, or the big social media giants should be broken up to make way for competition.
By the way the same should apply to all big media empires such as Sky. It’s not right for particularly large organisations to control the flow of ideas.