I think the tree stand walker got it's head smashed on the way down. It looked like the back of it's head was caved in when he rolled it over to search it's pockets.
They did show Dwight watching VHS tapes of Charles in Charge or something a couple weeks back when they had the Daryl-centric episode, so I assumed that's what he was talking about, but it did sound very out of place.
They are really going out of their way to make sure we see just how brutal and psychotic Negan is. While it certainly makes viewers more invested in seeing his eventual downfall, it also makes for an increasingly unbelievable scenario with Sanctuary and the Saviors. For example, the wives. If all those women have someone else in Sanctuary whom they were originally involved with, that would make for a whole lot of animosity towards Negan. Couple that with the fact that there is obviously a huge gap in the caste system in Sanctuary, and that even the soldiers aren't treated particularly well most of the time, and it's nearly impossible that he's managed to hold onto power as long as he has without an armed insurrection (which is how I assume he will be taken down eventually).
Also, I'm sorry, but Carl shows up ready to kill Negan even if it means sacrificing himself, and an hour later Negan turns his back on Carl to address the peons, no guards nearby, and Carl is holding Lucille...but does nothing. One swing Carl...one swing.