I suspect the crosshair tool simply does not work well or at all on touch devices, unfortunately. It’s actually unclear how a crosshair tool would be expected to behave on a touch device, I think someone with much more touch UX experience (than me) would need to to fist make a proposal about how such a tool should even work from a user perspective.
I suppose one option would be to make the crosshair tool act like a drag tool on touch (so it would be exclusive of pan and selection tools, etc) But it’s currently a foundational assumption that “inspectors” do not conflict with other gestures like pan/drag, so this would be a really large change to figure out and implement without breaking lots of other things.