Since my previous posts were all hidden, I'll try to convey the same basic message without using any of the no-no words:
Systematically killing innocents is bad.
Saurfang was there when Blackhand's Horde did the same thing. It was bad then too.
Saurfang experiences PTSD when he sees it happen again under his new warchief. For good reason. It was very bad.
Sylvanas is a villain.
Sylvanas is bad.