Having fans is like having millions of really strict parents. You have to live in a bubble and can't make mistakes or else "arm chair quarterbacks" (like message board forum posters) will grill them over every decision, even if they made the "right" call but it didn't work out. Hell, even if they made the right call and it did work out, managers are likely to hear it from some of us. (I think we'd all agree some fans/posters aren't the most logical)
Simple freedoms we take for granted, such as saying "f*** the Yankees" or "damn that ump sucks" or telling Jacko to f*** himself, managers don't have. If they say what's on their mind, they can be fined, fired, or both.
Then again they get paid a lot so I don't feel bad for them.