If you're not familiar, the notation tl;dr means "too long; didn't read". That doesn't apply specifically to the UUA -- liberals can't seem to make a brief statement anywhere -- but does include it. A long written thought could be deep and generous, but they're usually crowded and undisciplined. The caveat kills, the editor giveth life.
I wouldn't expect you to slog through a long work of mine, either. That's why if items in this series seem short -- well, that's on purpose.