Spoiler alert.
What Negan did was awful, but he did it as his position as a leader in the way he saw fit for the sake of maintaining his role of power and keeping people in line. I recently saw the episode when he kills Abraham and Glenn, sure it's brutal, but he did as he said he would and always maintained his word. Rick has done things as well to others that may not be as brutal, but just as bad and has show he can lie to get things his way. Negan after being released from his cell has proven himself time and time again to do things for the greater good. I can't list all at the moment, but he has what some would say redeemed himself and proven his worth. Maggie continues to have the hatred for Negan throughout Dead City after the countless times Negan has stepped up for the communities. Nothing Negan can do will bring back Glenn nor Abraham, but it gets tiring having her harbor the hatred after so long on someone that has saved coutless amounts of people along the way. Not to mention, they go on a mission to save that brat of a kid that can't stand his own mom, Maggie. Negan left to be on his own, but Maggie had to use Negan to try to save her kid. It's jusy silly after a certain point. Also, I think Glenn's last name of Rhee is mentioned in what feels like every episode after a certain point after his death, like give it a rest lol it's like the writers just gave up.
I haven't finished the comics as I am straight up procrastinating, but I know the show has taken liberties in changing storylines etc. Just saying in case the comics are actually following along with the show at this point, which I doubt.