parse error. 1. Yavor Doganov says something. 2. Wouter Verhelst: Yeah. _We_ know. 3. Yavor Doganov: Is suddenly "sad" that Wouter (seems to) agree(s). WTF?
I assume that by 'preching to the choir' Wouter meant: the people you are trying to convince already believe in what you are saying. I suspect that Yavor interpeted this as: the people you are trying to convince don't care.
The first meaning is the correct meaning, however due to the strong negative connotation of the phrase it is not uncommon to misinterpret it.