Some good points here, meaning the symptoms will be right wingers claiming racism and diversity of ideas etc etc. Having been conservative once, I too fell for the bit about diversity of ideas not race or background. But now that I’ve learned and traveled some more, I know it not to be much more than a smokescreen.
The reason behind this is the one thing you get wrong by claiming that these viewpoints are so far from center, so fringe, that they shouldn’t be allowed to sneak in. If only it were so. No, these racist views are scary because they indeed speak to what most of this land’s powers believe and what informs their actions (see mass incarceration, drug laws, arrest rates, foreign policy if you must look deeper). That is why there is such a reaction: many of these ideas hold sway and they do a lot of harm. If they didn’t we would in fact treat them like flat-world or spaghetti monster ideas.
Once you realize that, then you can see why the diversity of ideas mantra is a canard. It’s just the powers that be that want to crush all comers (and especially minorities) ideas be damned.