Excited delirium just won’t go away. No medical association recognizes this condition as factually true. And no cop shop will ever move away from using it as a handy excuse for in-custody kil…
If you never looked into what excited delirium is, or at least what it's claimed to be, it's a wild fucking ride. It's a rabbit hole that you probably should not go down but I still recommend trying.
tl;dr: "Excited delirium" is a thing that was made up, is not a real thing, and is used by medical examiners to excuse police for murdering (usually non-white) people.
Even if true, which it's not, it's not a risk to let a handcuffed man breathe. Putting your knee on their neck isn't going to help hold them down any more than anywhere else most likely.
Everyone is aware of the kneeing of a person's neck, even cops, continuing it even now is so frustrating.