There may be no systematic way to draw the line between dangerous opinions that need to be silenced and those that do not. There may be many people who draw that line incorrectly.
But that doesn't mean there is no such line. Almost everybody agrees there should be some cost to expressing highly dangerous views -- where we disagree is what that cost needs to be for a given view (reputational, financial, capital).
And in this hypothetical world where having dangerous opinions has consequences even though sometimes we draw the line incorrectly, I'm assuming you think your personal views could never be marked as such? We still live in a free society where at least the aim is to not hurt people in any way for expressing their own views.
But that doesn't mean there is no such line. Almost everybody agrees there should be some cost to expressing highly dangerous views -- where we disagree is what that cost needs to be for a given view (reputational, financial, capital).