Why do you care if there is more people discussing one thing or the other? how does that affect you, and why do you question that it affects other people? the movie has its separate thread, much larger than this one, and I don't see what's wrong with commenting the shooting, or why it would be better if more people were discussing the movie. You say people who feel empathy for real people's suffering don't have any connection with the victims whatsoever, but you surely feel a deeper and more valuable connection with a superhero film, right? The film is worth commenting, but nobody should dare say a word about a mass killing, right? Your questionings don't make any sense, and I hope you acknowledge that.
Personally, I haven't seen the movie and I don't know if I'll watch it, but I heard about the shooting on Friday morning and was shocked. Honestly, I can't relate deeply to the pain of the victims and their families and friends (although I wish they can find some consolation), but the thought of someone coldly planning killing innocent people that just happened to be watching a movie is horrifying.