"Modern people"? Get over yourself you hermit. The people ain't acting either coz they're in shock or fear for their own safety. I'll be honest, I'd only do something if:
A) There was a bunch of us helping out; or
B) If I had a long or long-ranged weapon
You see a guy munchin on someone's face and you don't know what the fuck's goin on. I don't want the cunt bitin me and infectin me with AIDS or some shit. Give me a baseball bat and two or three other people, I'd do summat, but if I'm stood in an enclosed space, no guarantee of back-up, and nothing to use as a weapon, I'm gettin the fuck outta there.
If it's someone you know, it's a different thing, obviously, but I probably wouldn't get involved if I was there. Especially bein surrounded by Chinese. I've seen plenty of news articles about terrible things happening over there as they just walk by and ignore it. Babies dying in the street, hit n run victims, and now this.