> Twitter shouldn't decide for me what I may or may not read.

Of course, but Twitter doesn't do that and never has. You are still very able to read what the New York Post writes by typing https://nypost.com/ into your browser, and Twitter's not going to stop you from doing that.

Twitter has a 1st Amendment right to decide what you may or may not read on Twitter.

Twitter doesn't decide for you what you may or may not read. I imagine you got here from some path other than Twitter. Therefore, you reading this reply to your comment comes irrespective to Twitter deciding what is allowable on their platform.

If the moderators of this site decide my comment is out of line with the standards this site tries to uphold, does this make me unable to communicate entirely? No, I'm still able to write whatever nonesense on plenty of other websites. Or I can host my own website where I can freely post whatever nonsense I choose to post. All the way up to the point where no ISP will offer me an internet connection or all the regional number organizations refuse to give me even a single IP address.