Because that thread is there to report Server issues, NPCs are something that technically are working just fine, or even better than expected! Also, this discussion in a separate thread would get more chance of being discussed, than a Q_Q Post about NPCs in that thread (which would either be ignored or lead the thread into complete off-topic). Yes, if server would crash when I had 12 NPCs on me, I would post there, but now, there is no technical issue with them. That would make an off-topic post for that thread.
Oh, and about reading Cannon's third post, been there, done that! That is why I'm saying reducing number or firepower of NPCs is not the solution, because I've read cannon's Post.