So these 3 get to decide whether your opinion is valid

So, if you are a CEO of a free-speech platform, you get to pick and choose Which opinions are valid? Doesn’t the constitution and first amendment protect the rights and free speech of ALL Americans? Have these three CEOs been granted special authority to over-ride the constitution and violate the free speech American of citizens?

If these CEOs determine an opinion to be questionable and censored, shouldn’t there be a process and a non-affiliated unbiased third party to make that decision? An arbitrator, combined with folks from both sides of the spectrum to ensure fairness?

Shouldn't there be an appeal process to ensure Free Speech rights are NOT violated?