You are right but badly oversimplifying.  There were an awful lot of other preconditions in Weimar Germany that allowed Hitler to come to power that you are not mentioning.  Badly fractured (many factions) political system, bad economic situation including the great depression, and extreme unhappiness at the perceived unfairness to Germany of the agreements that ended WW1.  Hitler's evil genius was to manipulate all these (and other) factors to lever himself into power.  I don't see those preconditions here.  There is no fundamental problem with free speech.  Yes, it allows vile groups to get some airtime.  It also allows non-vile but unpopular groups to get attention and sometimes that is important (e.g: women's rights.  Not popular at all at first).  Do you have an alternative to free speech you would like to propose?