I don't know about Brazil, but in Argentina that would be the correct ruling according to the law. They probably didn't think they could actually kill someone. In the worst case, they thought it was possible, but too improvable. Plus they were drunk. So you may not like they laws, but these rulings alone do not necessarily imply corruption.

In Brazil that would be true in the case of a regular car accident, it would be regarded as having no intent to kill.

If you are drunk however, brazilian law understands that you had intention to kill, because you know well enough that drinking will impair your driving and most likely kill someone.

However, an officer's statement is not enough to prove that you are drunk, you have to agree to take the test, and if you don't, than you can just throw money at the case up to the point where the final ruling is so late to the fact that the penalty has expired.