Thanks for the link Mr Optimistic.
I was already familiar with most of it, and I am quite familiar with how a supesonic intake compresses the air.
The link confirms my earlier comment that the TOTAL PRESSURE reduces as air flows through a shockwave.
But nothing in the link explains how the thrust exerted by the STATIC PRESSURE acting on the rear surfaces of the intake, can be greater than the drag exerted by the TOTAL PRESSURE acting on the front face.
I don't think that anyone can sensibly deny that the increased pressure and density caused by the intake will increase the thrust produced by the engine.