This isn't about Rondo. It's about LeBron and, to a lesser extent, Wade. When they're locked in, they have the ability to shut down any perimeter player in the league, with the possible exception of Kobe.
Last year, Derrick Rose was the MVP. Yet when LeBron switched onto him in the ECF, he couldn't score. I don't think it's fair to grill Rondo for his performance; LeBron is just that good.