I've never seen a UI animation that quick. Most UI animations are hundreds of milliseconds. And even if somebody did make one, it would still be annoying. Even a little latency is enough to break the sensation that the computer is part of my own body, and instead make it feel like a third party I'm commanding.

I can’t see I’ve ever felt like a computer is part of my own body. And I’ve been writing software for close to 40 years.

Either you’ve been using only crappy computers/software then or you’re not getting what they’re talking about. Do you feel like your car is an extension of your body when you’re driving? Because science showed that’s exactly how humans behave when driving. This is how our brain works with automatic motor functions.

Literally nothing happens instantly in real life, why should it be different with computers?

All hands tools (including common things like pencils and toothbrushes) react to your movement with zero added latency. Computers should be the same.