Yea I heard all about that. I seriously doubt somthing built like a t-rex was intentionally built to be a scavenger. Truth is predators scavenged if they could anyway. It's easier. Lions do it all the time. So I'm pretty sure T-rex(as well as everyone who was lucky enough) wouldent pass up an easy carcass, none the less T-rex would kill for food as per design, just as sure if ylou dropped a Great White in a pool of seals.
I believe Jack Horner was a paleontological advisor on this film, and, if so, probably pushed that scene to try to convince everyone outside the scientific world that his (rather cockamamie) theory that T-Rex was a scavenger