The only times I ever seen any major backlash towards a character death is this was Glenn and I'm not getting into that anymore. And Carl who regardless of how you feel about the actor was considerable by many to be unkillable due to him being the secondary main character.

Aside from those two I can not recall any type of major controversy from killing a character. You think anyone would have been that upset to see Gabriel die in Season 10 like he did in the comics? Or for Kelly to be killed off earlier in season 11? I don't think they would have been upset for Carol or Daryl to die in the final season. I mean people loved the pike scene in season 9 and it was one of the biggest mass deaths in the franchise. The character deaths is not the issue. It's the writing choices that's the problem most of the time. It's just annoying how people use two very poor writing decisions to justify Walking Dead no longer killing characters. When the vast majority of deaths in the shows no one has any issue with. It was just two death that sparked controversy the reasons for which have already discussed quite a bit.