Smart people are finding it difficult because it's absurd to accept that gigantic monopolies are allowed to control the free flow of information.

I can't even go out and speak in a public square, because it's illegal. Internet censorship by corporations is still censorship.

you are right from a constitutional perspective, but it's somewhat misses the point.

Private censorship is still censorship, particularly when the public square is privately owned.

if we can't stop the tit for tat between left and right from escalating further I truly fear for this country.

To be clear, you're referring to "the right, led by the President, organizes and executes a violent attack on the Capitol, so companies refuse to continue providing services to those people" as a "tit for tat".

There is a difference between cases when business needs to spend effort to assist you, and when it needs to spend effort to prevent you. Here preventing is actually harder, because there is no difference to AWS/Twitter which combination of numbers it stores and it has to go out of its way to read the number and block specifically your speech.

The dominant cost here isn't the cost of the employee that has to update their database, it is the cost of lost advertising or customers angry that your company is providing services to terrorists.

If twitter had done this for advertisers and the customers, their price of their shares would not fall.

Agreed. And, if I don't want to make a cake for a gay wedding no one can compel me to do so.

Certainly a relevant comparison, but if sexual orientation is, like race and gender, a protected characteristic, then it may make sense from a balancing perspective to not allow that to be a valid reason, even if "affiliation with a terrorist group" remains a valid reason to choose to deny service.