I was there the day Mattie Forde jumped on someone's head and they showed it over and over again on the big screen, driving the crowd even more bananas at each showing. That said, I don't think there was ever any suggestion of the crowd being driven to violence.
Anyhow, since that day, they stopped showing all the dirt on replays. I suspect the only reason they showed Philly's tackle back was that it really didn't look like much on first viewing. It's only in slow mo replay it looked like a box in the head.
I'm inclined to agree though, they should show these incidents back, and if it helps officials to make the right call, even better.