Depends upon their involvement with the government that allows them their market position. In the particular case of CloudFlare I don't actually know what the

Depends upon their involvement with the government that allows them their market position. In the particular case of CloudFlare I don't actually know what the involvement is, and would default to agreeing with you. But I do know some private companies often mentioned in relation to First Amendment that there is some level of involvement, but I think the courts have largely not taken a critical look at what is going on and is still quite inconsistent on the matter (which should surprise no one who compares the pace of law and the pace of technology).