I'm not sure how it's being presented in Brazil either, I'm not there. But well, the thing is: someone gets a gun pointed at them, they generally know not to move and the police officer generally knows not to shoot unless he's prepared to use lethal force. With tasers, they just think it's oh-so-fine to spray shots because they're non-lethal.
There's nothing wrong with cops in Brazil btw, not wronger than any other place. People just say that because they're communists. I'm not even kidding.