Taking the other side, how do you counter the "So some opinions are okay to state publicly, while others are not?" I think this is the rub... For any given X, you'll find groups of people that are pro-X, and someone anti-X.
If you say "taxes are theft" I may disagree with your viewpoint, but I'm not personally attacked by it. If your viewpoint is a challenge to their personal identity, you should probably keep that to yourself.
Edit: just as a final thought, I've been on both sides of this, I've been silenced and I've silenced other people and honestly they both suck. I hold this view with the believe that some middle ground of things not being okay is the only one that works. If someone thinks that a free for all of ideas works well they are welcome to try it on their social media and at their company and I could be convinced if I could see it work at scale. It's really a practical view more than a philosophical one