their values

You are too quick in ascribing incompatible values to people you disagree with. That's the cheap way out; it allows you to write off their opinion without considering the fact that they might have the same terminal values as you, and arrived at their instrumental position for rational, empirical reasons. Then you'd have to actually consider whether their position is correct, instead of just writing them off.

Extreme right-wingers all seem to share the explicit values of institutionalized dominance, rigid hierarchy, rejection of universal ethics and the suppression of any threat to such an order.

This is the straw-man version you get taught about by the Universalist establishment. Don't take it seriously as what these folks are actually thinking. Some people are just dumb and evil, and most confuse "this is instrumentally a good idea" with "this is terminally a good idea" but there's less of them than you are taught, and there actually are good reasons for the apparent craziness.

It is perfectly possible for someone to have the same values as you and consider (the non-straw) version of those things to be instrumentally a good idea.

I have pondered where those ideas might lead, and it fills me with equal part horror and rage.

I don't know what you are thinking but I know that feel. I had that same feel just a few months ago. I used to look at authoritarians, racists, PUAs, and such and think. "what the fuck is wrong with these people? How could they be so wrong? Are they evil?" mostly I just felt that horror and rage though.

The truth has a certain ring to it. I first noticed that truthiness with LW; "wow, these guys get thinking right", then a while later, with MMSL (married PUA) "Wow, this stuff is totally different from what we're taught, but it works (on my wife)". Then with do-ocracy, and authoritarianism "wow this just works so much better for meetup organizing". Then with HBD, when I realized that I could build an acceptable line of retreat in the case that the racists were right on the factual questions.

And then, to quote moldbug: "for a wide variety of controversial issues, it would be very, very easy for any smart young person with a few hours to spare to see what the pattern of truth and error, and its inevitable political associations, started to look like." That is, the "Dark Enlightenment" convinced me, a former hardcore anarchist.

So please, please consider that your enemies are not evil mutants. That people might reject democracy, and accept dark enlightenment ideas for actual good reasons, not just because they have magical "incompatible values". Please, please consider that you may not have all the facts, and that you may end up changing your mind on some of these issues.

I wish for a broad cordon against it,

Please don't. What if you're wrong? How will you realize your error if you put in hard blocks against certain ideas?