T-Rex: Scavenger or active hunter?

Sometimes paleontologists make other paleontologists cry. One of the biggest debates between paleontologists recently was Jack Horner versus practically the rest of paleontology over whether or not Tyrannosaurus rex (and all other large theropods) were predators or scavengers. Horner was on the scavenger side, and uses arguments such as: The size of the animals is more conducive to scavenging (scare smaller animals from kills); their legs were designed for walking instead of running, and being so large any form of moving fast would endanger them by off-balancing their bodies; they can only use their mouths for attacking, which is dangerous; For T. rex specifically, the large olfactory lobe of the brain (meaning excellent smell) and the small size of the forelimbs (which prevented T. rex from holding prey with them), and the thick armor-piercing teeth and bone-crushing jaws (for breaking apart bones to get the marrow inside). The rest of paleontologynote counters with:

As prey size increases, generally so does predator size. Every prey species has at least one predator that can take it down (at least at some point in its life).
The structure of the tyrannosaurid hindleg is similar to that of the ornithomimids, which were clearly cursorial.
Even if they couldn't run, the large theropods would have still had a brisk walking speed, and their prey wasn't designed for speed either, favoring either keen senses, armor and weapons, or herding for protection.
Many animals today use only their mouths to attack.
Tyrannosaurus also had binocular vision, a primary predatory adaptation. Many predators also use smell to track prey. The forelimbs of T. rex are also very heavily built with numerous strong muscle attachments, and they're designed to twist and pivot, which shows they could easily withstand the forces of struggling prey. As for the teeth and jaws, again modern predators show that bone-breaking isn't a scavenger-only tactic (hyenas, the master bone-breakers, hunt more than they scavenge; breaking bones allows them to extract more food from a kill).
Healed tyrannosaur bite marks have been found on Edmontosaurus and Triceratops bones. Since dead things don't heal, they must have escaped the tyrannosaur, showing that it actually hunted.
Finally, the only true vertebrate scavengers are buzzards, vultures and condors - creatures that can cover vast amounts of territory with a minimal amount of energy expenditure. No animal the size of Tyrannosaurus could live as an exclusive scavenger, as it would use too much energy searching for carrion. Tyrannosaurus also was the only large carnivore alive at its time and location, so if it wasn't killing large prey nothing was. And most predators are also scavengers. They'll take whatever food is on hand, which is a must for creatures that don't have a reliable and easy food source the way herbivores do.
Horner has acknowledged that Tyrannosaurus was an "opportunistic predator" (which is what everyone else thinks to begin with) in the only scientific paper he ever wrote on this subject. (Although he did popularize the scavenger hypothesis in books and TV shows.)
Note that the debate also runs on a False Dichotomy: scavenging OR predation. In practice, most carnivores like lions, hyenas and jackals do a bit of both.