Skycop
You ask what glider pilots are told (pretty basic stuff).
Same as us power pilots:
Aviate, navigate, communicate (in that order).
The difference when I don't have a constant source of guaranteed energy, is that a higher proportion of my time is spent on the first priority. In my case, that is prioritising and minimising risk.
If you are seriously concerned at a minimal risk, occurring in predictable conditions (isolated towering cumulus that you almost certainly don't have to fly through), then listening briefly on a known frequency will reassure you. If you want further reassurance, then investing £400 in a FLARM will guarantee you won't bump into me, and probably not into a growing number, soon a majority, of cross-country glider pilots.
If you want to complain about another sector of the aviation movement, instead of analysing the relative risks (study the accident staistics in your own aviation sector), then carry on, but please don't expect me to respect your logic (or lack of).