There's a lot that could be said on a fact-by-fact basis to support Moore and to dis Limbaugh, but I'll just stick to this for now:
If you listen to them long enough (and I've spent many hours listening to both of them - although Limbaugh has certainly spent many, many, many more hours spewing hot air than Moore has) it becomes pretty clear that Limbaugh cares about very little beyond himself, his ratings, and his insatiable ego. He couldn't care less about anyone beyond himself and perhaps a small handful of his immediate loved ones (I'm thinking mostly his mommy & daddy and his little right-wing brother).
Moore, on the other hand, genuinely seems to care about people other than himself. If he didn't I think it would be extremely tedious and boring to make a lot of the films and tv shows that he has. If you couldn't give a rat's ass about the people of Flint, Michigan (or the USA overall), it would be hard to take the time to make films about its downfall....
I'm sure Moore's got his foibles, quirks, and flaws - he's human, too - but he definitely has his heart in the right place and isn't willfully ignorant and reckless and bellicose like Limbaugh the hate-filled bastard...