Re: It beings.
"While I disagree with what TDS says, I will defend their right to say it."
They have a legal right under the First Amendment to say their piece without government interference.
However, nobody is required to help them say it. This includes businesses. If TDS doesn't like this, they're free to sue.
"...very quickly the scope creeps and we have all manner of things being banned, usually by a very narrow and vocal group of far left / Marxist / Social Justice types."
Usually? I can name a number of right wing organizations and governments where freedom of the press is not "a thing". Read some history. You could start with Nazi Germany (since we're talking about TDS, this isn't a Godwin)