Why is spatial mapping considered a 'dangerous permission?'

One of the USPs of a true MR device, is the ability to interact with reality. Why on Earth then is that a thing you must ask permissions for? It's like a car needing to ask for permission to put itself into second gear.

The reason why Spatial Mapping is considered "dangerous" is because it can contain private information, such as the layout of a secret location or a secret object. You can see the same consideration on other XR platforms that require the user to agree to sharing the mesh data with the application.

Is your main concern having the user accept the permission or about the process of having to manually create a script to request it?

I am not aware of 'other XR platforms' asking that, in any case HoloLens does not. I am not sure about the Quest, still have to get myself a 3