A business that is impossible to get into without the "blessing" of the industry its in is the very dangerous circumstance that monopoly and cartel control of an industry creates. Glenn got the summary of the problem correct without getting the details right.
If Parler's business were illegal, the government could step in and shut them down and the service providers wouldn't need to do anything at all.
The other poster below you was quite right in that the US government is using its monopoly on force (and the threat of it) to effectively bully the service providers into denying them service. Illegal or otherwise (the judiciary/military version of "fuck around and find out"). Ideologically they just happen to be more than willing censors here.
If Parler's business were illegal, the government could step in and shut them down and the service providers wouldn't need to do anything at all.
The other poster below you was quite right in that the US government is using its monopoly on force (and the threat of it) to effectively bully the service providers into denying them service. Illegal or otherwise (the judiciary/military version of "fuck around and find out"). Ideologically they just happen to be more than willing censors here.