It's a fair comment though - there is a problem, and it's not just that anybody working hard enough to keep a Jaguar in the air will struggle to see and avoid a 747.
Gliders can't be painted in dark colours- which will attract UV and damage the composite structure. They can't carry transponders by and large, because there's no power supply. They can't fly standard IFR or circuit patterns, because they don't have engines that allow them to maintain fixed headings and altitudes. None of these are readily solveable.
There are a few things that could be done - glider pilots could be better educated in circuit patterns before they start cross-country flying. Also, I'm afraid that I've no sympathy for the "we're glider pilots, we don't have to learn RT" view - picking up a FIS on a handheld ICOM takes little effort, and is a big aid to themselves and everybody else. Similarly, there is no good reason why a diverting glider pilot has to join an airfield non-radio - standard circuit calls and a standard-ish circuit are entirely achievable.
The other thing that I'm surprised isn't done is carriage of a Luneberg lense - that is one of those strange right-angled metal things you often see hanging from the mast of yachts. It wouldn't be hard to build one into the fuselage of a glider and it would make a huge difference to primary radar returns. I believe that stealth fighters fly in peacetime with something similar - it makes life much easier for them, as well as the obvious advantage of making sure nobody knows what their wartime radar signature looks like.
Yes the rest of us can, must, and do maintain the best lookout that we can - but ultimately the glider boys and girls do need to help themselves a bit more.
G
Getting reactionary in my old age.