It's the same for these tech companies. They are private companies and if you break their ToS for inciting violence or posting illegal shit then they have the right to ban you. You have freedom of speech, not freedom of consequences.
Well, if that "private property home" is the only place where people in your surroundings can get something to eat; and if that someone "spew at others" but says something vile quietly to his friends, so that only people actively listening in on the conversation hear it, then - maybe you should not be able to police what that person says.
Note I said internet service not a subscription to a social media service. Your internet provider may decline to provide you with email, hell the may even decline you to provide with you with DNS, but they sure as well can't refuse to route your packets or accept incoming connections.
Apple and Google were within their rights to cut off access to the App store, but Amazon were in the wrong because they are an infrastructure company. At the very least they were obliged to allow Parler enough time to transfer to new providers.
On the other hand, there are a thousand different cloud providers; surely at least one would have taken Parler on as a customer. And even failing that, it’s much easier for Parler to run their own servers than it is for me to run my own power plant.
All of us here in the US are entitled and reserve the right to do business with whom we want as long as it doesn't violate discrimination laws, which focus on race, religion and things like that - not opinion about whether there are lizard people ruling the government or that an election was "stolen" because a few people made up some good stories about it but there is no actual proof that can be viewed in person...at all.
When those oligopolies act in concert or along the same ideological lines what options do you have?
E.g. the authorities can seize cash from you as has happened to store owners who went to deposit it at the bank. If every bank refuses to serve you which you claim to be their right, then why do you have laws which to criminalize cash holdings if that forces you to withdraw your cash from them and hold it in the street or at your home?
One cannot criminalize large cash holdings arising from cash payments which is okay with many people while at the same time giving banks the right to deny service.