re: Walking Dead s8 episode 5 "The Big Scary U"

Negan mentioned to Gabe that the sanctuary was a mess under the previous leader when he first showed up and he took over the place.
I guarantee that Simon used to be the leader of the saviors(the one that ordered killing every male in the oceanside community)
And now that negan is in charge, that’s what he was referring to when he asked Simon if he was “backsliding”
Negan no doubt broke Simon the way he does his soldiers.
When Simon suggests slaughtering the entire hilltop, Negan became furious asking Simon if he was backsliding.
Negan wouldn’t have slaughtered entire Oceanside male population. He values people too much As a resource.

This is why Negan knows people will die if he doesn’t get back inside to keep Simon on a leash.