A lot of people seem to think reactivity in 8s is basically just "someone punches you, you punch them and you go to jail." I don't think 8s are necessarily emotionally labile like that and I don't think that's what reactive means. I think there could be lots and lots of NT 8s, they aren't all 1s or 3s. When you look at control freaks, control freaks are mostly people who are not in control of themselves, and though that definitely can mean screaming etc., it doesn't have to mean that. If people don't feel in control of themselves, they often want to control other people, but that's not really control of other people if they aren't even in control of themselves, that's just a reaction. So it makes sense 8 is reactive, but that doesn't mean emotional lability all the time or necessarily any obvious displays of affect ever, even if it's not like it's impossible, contrary to what people mean by "reactive."

Take what C. S. Lewis said about the magician's bargain in his book The Abolition of Man. If you go sell your soul for power, that power isn't really yours because you already gave up your soul, you're basically just a conduit for something else at that point even if it's obvious people do that in order to feel some sense of control despite the fact they gave up their control. 8s aren't all out selling their souls but I think that's probably a much more useful way to think of the idea than just some stereotype of reactivity and imagining E8 must be about being a meathead who just reacts viscerally to everything all the time.

Then, I don't use any typologies for my main source of psychological knowledge, I was just describing the sense of control in people who have lost control with my friends and I incidentally referred to it as "reacting" and that made me realize it's not really that kind of emotional reaction at all even if people are definitely capable of screaming like a stereotypical drill sergeant while wanting to be controlling, people are also capable of acting quite cold and calculating while wanting to be controlling, but that's secretly reactive too because they're just letting their reactive feelings of not having control guide that.