I disagree somewhat.

The problem with the article is its theoretical level.

>The freedom of the intolerant should only be limited if the people holding totalitarian beliefs can no longer be “kept in check”, in the words of Popper, or is a danger to the public order, in the words of Rawls.

This implies a world where we can objectively agree on a clear line, and if someone stepped over it, we can all agree that this specific person can now no longer be kept in check and can now be suppressed. But the world is not like this. Everyone assesses from their own point of view, and may come to different conclusions. Fascist abuse of freedom relies on this: it pushes the boundaries, and when the first ones cry foul, they get support from those who do not agree with that assessment, and create division. And because the minds of people and the rules of the society are changed with enough support, the fascists can gather enough support by operating on the vicinity of the line to push the line further and further.

You say that we should only be intolerant of violence, not merely non-acceptance of our views, but if we wait until the fascists get to violence, it is already too late. They gather support by being intolerant, and if we don't suppress that, they are allowed to gather enough support that we will be unable to stop the violence when it starts.

I recognize the problem that if there is no universal rule, it is impossible to objectively say when are we not actually preventing the rise of fascism but simply suppressing non-acceptance of our views. This is a real problem. But I argue there can be no universal rule, because such a rule needs to be careful enough to not go too far (like you advocated), but a rule that is that careful is a rule that will not stop fascists.