It is not possible for corporations to violate the constitution. There is nothing in the constitution about what corporations (or any non-government entity) may or may not do.

Excuse me? Corporations are not people and are beholden to the government and all Laws that the government is beholden to. Unless you want to argue that Twitter is a person in which case they would also be beholden to not infringing on the rights of others. I do not see a win for this. NO ONE IS ABOVE THE LAW!