Cartel may be a better term, but the argument holds. The point is they collectively wield undue market power and function as a de facto collective in the use of that power.
According to the CEO of Parler, their bank and payment provider, law firm, and mail and texting providers all cancelled as well. What are you supposed to do then? Store cash in boxes? Receive cash through mail?
Parker was destroyed when their business partners exercised freedom of association and cancelled on them.