Censorship is systematic suppression of content considered by the censor to be morally or ideologically objectionable. “Censorship” is a scare word like “discrimination” and “sexism”: it has its legitimate applications, but it is sometimes used to alarm and manipulate and bully.
If a given medium or outlet, privately owned, declines to give a platform to some particular view or expression, that is not censorship. They are not doing anything to prevent the author or originator from putting their views before an audience; but they are declining to provide their own platform for that purpose.
They can’t do a thing to stop the author from presenting those views elsewhere. If they could, that would be censorship. They’re not muzzling the speaker. They’re saying “You can’t use my bullhorn.”
A government or other comprehensive institutional structure has the power to censor, but in practical terms, a private enterprise does not.