Earlier quoted context omitted.
I know, but users without touchpad had zoom functionality (like ctrl+wheel or ctrl+scroll) for years. Don't get me wrong I like the zoomability of a calendar, it is an excellent way to visualise information.
Managing both is very difficult, at least until we get pointer events supported ( http://caniuse.com/#feat=pointer )
I agree that it will be great to be able to target touch pads or mouse/keyboards but I believe it is pretty simple to fix the UX on this app.