Though I guess you could still reasonably argue Barbara being used as a prop is problematic, but I don't see how that merits enought hate to say it should be erased from Batman continuity.
The reason is: Batman is famous, easy as that.
Most SJW sing with their choir and wait for the next big thing to flock around and shout at, something they can call something-something-phobic. They are looking for easy targets, like popular culture, news, games, media and so on, whatever spurs the biggest reaction from "the other side" at the given moment. I doubt that any SJW-tumblrista will take some form of real political initiative and try to actually change something, that lies outside of current media or affairs. No SJW will sit down and calmly explain someone why something might be problematic, nor do they take the time to look at the subject in question from at all angles, because then it wouldn't be an easy target anymore.
Being a generic SJW is not about changing anything, it is about being heard, being taken serious, acknowledged and accepted. The cause does not matter, but the group does, although they might tell you otherwise. SJWs are about being 'unhappy', 'scared' and 'angry' and to have something to throw their anger at. They are "mad as hell and not gonna take it anymore", but they don't use their anger in any productive manner. SJWs scream until someone says "Okay, shut up already!" and although this might bring a change, it is not by changing peoples minds through facts, but by bulling concessions out of them.
Sometimes they even hit the right target, but at this point they are so desperate to find popular things, which they can call misogynist, they have to complain about a comic that was made while the Soviet Union was still around. A comic that was made 27 years ago, when most of them weren't even born. Even if "The Killing Joke" was problematic at all, it would be like complaining that "Mein Kampf" is a book full of fascist ideas. SJWs don't look at circumstances and intentions, they just want to
troll and have the illusion that they have the right to do so.
All through the 20th century and up until now, brave women and people from minorities stood up for equal rights and changed the world for the better ...and these guys want to pick up the torch.
This makes me sad.