Social media companies try to portray themselves legally as platforms in order to eliminate legal liability for the content that users post on their platform.
Either way from a moral perspective doesn't change the fact that a platform censoring viewpoints is a violation of the principal of free speech, and morally reprehensible in a free democratic society. Twitter tried to be the Orwellian Ministry of Truth, and I'm glad that Twitter's new management recognizes the error of their former ways and is committed to not repeating the same Orwellian mistakes.