I'd just be happy if it let me use the multiplier; don't care if it's not exactly pixels.

> Apple probably also didn't want to translate multitouch to scroll in hardware,

That much doesn't seem unique to Apple; both Windows and Linux appear to prefer accepting raw multitouch data.

> since scrolls are not reported the same in all contexts (e.g. applications can choose whether it locks to an axis; which axes it can lock to depends on the capabilities of the view; etc.)

I don't think they're actually taking advantage of this. My MBP's built-in trackpad will lock into pinch/rotate gestures when the cursor's over say Zed or iTerm2. (Zed's a bad example actually, as it has no accessibility tree to speak of. But I think it will lock into pinch/rotate anywhere.)

And for my own app, as far as I know (I'd be very happy to be corrected) there's no way to inspect a view to know what kinds of gestures it supports. It certainly would be nice to eliminate the possibility of locking into pinch/zoom in a place where that's meaningless but I don't see a way to do it.

> Applications can choose to ignore synthetic events, IIRC. Probably not an issue for scrolling, but for instance Little Snitch can be configured to ignore synthetic inputs to its security settings.

Yuck. I'm doing everything this way, including cursor movement and taps. I hope I don't come across such an app/configuration.