I can see all of the points you make Pete but:
Especially when the 'aggressor' is perceived as little more than unabashed commercialism
I take it by that you mean CAT operators flying outside CAS on direct tracks because it's more economical and more "green"? That is something that is unavoidably going to increase and with it the "hand-over" of airspace to growing airfields, (RHIDS
) for one and busier en-route sectors, the "part-time" airway between NCL and ABZ as an example, deemed necessary to protect transiting aircraft from Military operations over Northumberland.
Regardless of what you feel your sport does for society, the fact is that the sky is getting busier, there will be a need for more controlled airspace and therefore the appropriate equipment will be necessary for flight safety.
Nobody minds you flying your aircraft, known gliding areas are easy enough to avoid, but long cross country transits in gliders at any level just doesn't seem sensible if you're invisible to the technology that keeps us safe.
What effect do you think a mid-air between a non-squwaking glider and a commercial aircraft is going to have on your sport? A lot more damaging than having to fit Mode S i'd imagine.