As said before, there's nothing "indirect" about it.
The forces acting on the complete intake structure, which finally are part of the forces that propel the aircraft, are acting forward.
I am quite prepared to accept the possibility that the supersonic con-di intake produce sthrust directly, but I would like to hear an explanation of how this is achieved. If it simply a matter of the balance of static pressure ahead and behind the intake, then an explanation would help.
You're slightly confusing the issue, because we're now talking about supersonic con-di nozzles, where again the resulting forces on the nozzle structure act forward.
My only reason for including a reference to the convergent propelling nozzle is because it produces additional thrust indirectly. As we have already obeserved the force acting on the convergent nozzle is rearward acting.
I am aware of the fact that the divergent part of a con-di propelling nozzle produces thrust directly. In effect it is recovering some of the energy that would otherwise be lost when the high pressure exhaust gas expands in all directions behind the aircraft.
But even in a con-di propelling nozzle the force on the front (convergent) section is drag and only that on the rear (divergent) section is thrust. The overall resultant force is the sum of these two forces.
Similarly I accept that the force on the rear (divergent) section of a supersonic intake is thrust. But the force on the front (convergent) section is drag. Once again the resultant is the sum of the two.
What I have a problem with, is the idea that the static pressure inside the intake is somehow greater than the total pressure ahead of it.