To me it doesn't look structural, just cable routing. It is welded on to the underside of the down tube. However, I am not an expert, I could be wrong. I am only using this bike for road and dirt tracks, not downhill or jumps, so I wasn't too worried about it.
The alloy is very soft for a grinder. Here's what I had to do on my Norco Storm 2 to get the Tongsheng motor to fit: