Mein Kampf sold 240,000 copies before he became chancellor, so it seems like it was already an important part of the conversation. I'm not advocating for censorship, but obviously the argument that Mein Kampf is available therefore we should stop trying to limit violent speech is not a good one.
"Fire & Fury" sold 2.3 million copies. Did it play a role in Trump not being re-elected?
Strawmanning an argument is poor form.
Mein Kampf has existed and been available, and hasn't actually really caused any harm. That doesn't make it a better book but the hallmark of liberal society is that we can tolerate dissent while an authoritarian one can not.
They controlled who was allowed to express themselves and how. They limited everything to their message, even suppressing branches of science that didn't support their views.
That we as a liberal society can tolerate illiberal views is important. You should read things like Mein Kampf and the Unabombers manifesto - not because they are good but because you should know your enemy and how they think.