I also agree. The inability to modify the ‘inference’ (snapping) in SketchUp (SU) can be quite frustrating when tracing. Quite. Frustrating. And yes, I am completely familiar with SketchUp as a 3D tool. I’ve been using it since it launched in 2000. That doesn’t mean that allowing some ability to quickly turn off the inferences is a bad idea or that people need ‘understand that it’s a 3D tool’. IMHO, being able to toggle inference on/off is a reasonable UX request. SU can be so frustrating I will actually trace in another app, DXF export and import into SU to avoid having to trace in SU. For certain situations that is, sometimes that route is more of a pain than just playing the ‘SketchUp Zoom Trace YoYo’ game. 
I also tend to agree that this post should be in Feature Requests since that’s what this actually is.