Getting an appalled reaction from readers isn't that hard or difficult. Anyone can do it, if they're willing to ignore logic and reason. The best example would be the OYL Robin arc that saw Cassandra Cain turn evil. People were rightly appalled by that because it was a terrible story on every level.

Making Leslie responsible drags down the Bat books as a whole. Yes, the books need a dark tone. But there must be some light within that darkness, some hope so as to not make the narrative sufficating. Leslie was part of that light, part of that hope.

No longer. As Icon put it so long ago, paraphrasing, there is no hope in Crime Alley anymore.

(especially when you consider the message behind Cass' recently reconned defection, but that's another thread entirely)