Glider pilots in IMC are aware of their position very accurately, as otherwise they would risk infringing controlled airspace. They do communicate with others who are the greatest risk to themselves, and that communication is on a known and published frequency (although apparently you were unaware of that).
Before continuing to pursue what appears to be an obsession with clearly limited knowledge of the facts, please find out what you are talking about, as the gliding community on its part does.
That is fine, but it seems to be that gliders only communicate with other gliders. I am by no means anti glider - but when I fly in IMC I make all possible attempts to let other airspace users know where I am, by using a RIS. Gliders talk to each other on one frequency, which "we" may not be listening to as we have Com1 dialled into a RIS and Com2 on 121.5 or the next enroute frequency.
My advice to a cloud flying glider would be at a minimum to dial into the nearest LARS controller and ask for a RIS or report your position using a FIS. That way GA traffic with the same controller has a cat-in-hells chance of avoiding you and you the GA traffic. If the worst ever happens - a glider hits an airbus - you can bet that things will change for the worse for everyone.