I suppose my point is that circular objects don't have flat surfaces for you to grip; other surfaces (with edges) allow you to do so. Those examples are cases where this principle has been applied. In any case, you have a good answer.

Lacrosse Sticks, which definitely do experience similar amounts of torque, have a squashed hexagonal cross section for this reason; the corners and non-round shape help you keep your orientation. You can see ovular cross sections on sword grips from many cultures as well. Once again, that is to help keep orientation, and in the case of swords, keep good edge alignment.