If you swing a baseball bat as hard as you can toward someone, no matter where you make contact you're likely going to incapacitate that person. Unless you're a fucking soccer player who's never held a real wooden baseball bat in their hands before. I would think that in Europe the gunshot fatality rate is much higher.
But here in America where we know how to kill people with bats, I can see why the bat would have a higher fatality rate. If you swing a bat really, really hard at someone, with the type of fury and prejudice that can only come from having your life threatened or from the sort of raging mindset that drives someone to kill someone else with a bat, then any direct blow will pretty much incapacitate the other person long enough for you to kill him at your leisure.
Not so with a gun shot. They're loud and draw too much attention when fired multiple times. They also go off on accident during fights, which lessens the chance of a gunshot wound being fatal. Bats don't go off on accident; they go off with one explicit intent behind them: physical mayhem.