I don't really know what to think of the whole LT situation. Most people that analyze football, say the criticism is unwarranted and ignorant. Not sure what most players think, but the verdict is out as far as analysts go.
And logically speaking, when they say that Rivers showed heart - it doesn't mean that they're saying LT didn't.
The effect of a knee injury on a QB does not render him as ineffective as an RB. Both Rivers and Brady are primarily pocket QB's. They need to move a little when the pocket collapses, but they're not required to juke, scramble, and burst like backs do.