It is. But you get what you pay for. Programs like Cut3D and MeshCAM load files consisting of polygonal models. There are no curves in the models to follow.It would seem to me that it would be far more efficient to have a 3D finishing algorithm that did curve following rather than raster traversal..
What you're seeing, is just the way these inexpensive 3D programs work.
To get a 3D program with feature recognition, you typically need to spend at least $2000, and usually more. Much more.