perhaps the use of tragedy is becoming more graphic, more exploitative

I don't know. Back in the day, they accused Tarantino of being graphic. To this day, I don't know why he didn't simply reply "Shakespeare". Or any of his works, like "Titus Andronicus". Slaughtering an enemy's children and baking them into a pie and feeding them to him? Check! And they teach these stuff to kids at school. (Well, I don't know about Titus specifically, but they do teach the Bible and that's worse even than Shakespeare.)

Their approach to tragedy is not poetic--it's brutal.

I agree and disagree depending on the movie. Many will think Oldboy (the Asian version; but the American isn't bad either) is brutal and gory. I think it's a classic, and I think there's poetry in the gore and the story. So it's hard to say.

Sorry to hear about your personal experience. That might of course have played a role. In essence, we are most of us pretty disengaged from real physical suffering akin to the things portrayed in movies, it's all like a videogame to us now, so people are perhaps having the wrong reaction to them. I can imagine what the Nazi Zombie movie would look like to people who've gone through the real deal. But to the rest of the world now, it's mere entertainment.