The only moral principle I have here is enhancing flight safety for ALL. It's unusual that large civilian transport aircraft transit outside CAS below FL100, they may have to sometimes in order to reach certain airfields without CAS, Doncaster, Inverness etc. The solutions are (1) require everyone to fit the equipment or (2) establish more CAS. Which is better?
As for keeping the "big boys" in CAS, fine. But, as i've stated before, not all commecial operations can take place in CAS.
Then there's the question of the Military, they DO operate in the open FIR and do have to mix it with the rest of us...surely the fitting of Mode S helps them out as well.
It's not bullying it's common sense.