Glider pilots should not venture into clouds full stop as far as I am concerned
Ah, but, the gliders will tell us, us non-gliders are supposed to understand what does and doesn't make good gliding conditions, and thus what does and doesn't make good gliding days, and in particular what does and doesn't make a good gliding cloud, and then avoid such clouds in case there are gliders inside them.
I can do
some of that! - if I see an isolated cumulous cloud with a number of gliders circling round underneath it then I'm not going to fly through it "just because I can".
But that's about the limit of my relevant understanding I'm afraid.