My concern is more in the ones that aren't quite as stark. Role play that you are talking to someone that doesn't feel safe enough to tell you that they don't feel perfectly safe. Now, how do you know this? If they felt safe, you could ask. But, we have established that they don't, per the role play.
And this is a large part of why the conversation around "privilege" is so tough. At large, what we call "privilege" can be easily recast to more subtle dynamics of folks that are allowed to give voice without as much interruptions. Note, not none. Just fewer. (Note that there are obviously other aspects to this that don't necessarily make the recasting.)
What I'm describing is founded on both participants being well-intentioned. If one person interrupts another to ask for a clarification, or to let them know they are already aware of something, and the original speaker is threatened by it, I would say this is an unusual circumstance: someone with a preoccupation about being interrupted may feel that way and may need special treatment, sure. If they are uncomfortable about it, hopefully the well-intentioned interrupter is able to perceive that. If there is a combo of someone with this preoccupation + someone who is bad at reading body language, that would be unfortunate.
As far as that recasting of privilege, it's an insightful metaphor imo, but at the end of the day still just a metaphor: the dynamics of not having your voice heard in society are in practice just a separate matter from this communication style.
My brain (maybe this is arrogant but here we go) works faster than conversation so I have to work harder in wait cultures, but after years of this I'm 100% on board. I _super hate_ to be interrupted: I don't go on and on and I'm generally saying things I want others to hear. People think they know what I'm going to say, they almost never do. People want to interrogate a minor thing I just said, but it derails us all and wasn't the overarching point I was trying to make. On and on.
I'm not saying "don't ever ever interrupt"; sometimes it's critical to stop--respectfully--and clarify something important, like "aha that's what we're misunderstanding here" or whatever. But it should be like, "I know interrupting is disrespectful, but I feel like we could solve this right now, so bear with me." I think what most people in this thread are talking about isn't the occasional interruption, but the constant interrupt/overtalk style.
Anyway, maybe there are others with experiences in diverse workplaces (genders, races, backgrounds, etc.) where interrupt culture works, but I'm skeptical. I think in those situations you're always building mutual respect and team trust, and as such interrupt culture is out of reach. I disagree that these issues are separate from communication style--the medium is the message here and interrupt culture benefits people who haven't experienced barriers to interrupting/overtalking others--largely not women, but also not introverts or people with anxiety, etc. I think if you're "well-intentioned", you're taking those factors into consideration as well.
Eh, my impression is that he's extremely arrogant and doesn't care what anyone else thinks. He's deeply uncurious and consequently relatively ignorant. He rarely engages in good faith with the facts and merits, and frequently misconstrues them to suit his own ideology. These are not the acts of an active listener who wants to learn and be shaped by what they learn. They're the acts of someone who believes they've got it all figured out.
As far the actual signaling goes, AFAICT it's pretty built-in (though I can imagine in other countries for instance there are likely enough differences that you'd have to take time to learn specific signals): I can go into this style of conversation immediately with strangers as long as we're at least giving each other a little benefit of the doubt.