Well, there's no dictional in my Concise Oxford Dictionary. Maybe its not big enough (more than 1500 ages though, not that concise) or not modern enough.

Truly, I thought there might be a typo, since the idea that the fact that someone mangles their speech a bit by schoolroom standards - which is what I guessed it might mean - might get in the way of their ability to stir an audience, well it just didn't and doesn't fit with my observation.

I agree that throwing Hitler round in this context isn't too helpful. It threatens to derail the discussion, because it's so easy to point out significant differences, and then the risk is people might be tempted to believe that just that just because the guy isn't that like Hitler is ok really. That also applies when you talk about deeply unpleasant people like Saddam Hussein, and Bush and others have done that freely. Compare just about anyone with Hitler and you make them look good.