I think you're mis-reading the situation the rotation of each individual shape isnt destructive (been following the author's work for a while, this is a vector

I think you're mis-reading the situation the rotation of each individual shape isnt destructive (been following the author's work for a while, this is a vector based solution) what he's talking about is rotating multiple nodes at once around a common center, so each individual shape receives a new rotation but also a translation. as an artist who uses these kinds of tools, and someone who'se had to design easy to use interfaces, it's hard to convay "invariant center of mass" when the selection for multiple shapes usually involves drawing a screen aligned rectangle (which has a convenient and intuitive center point)