Doing something bad doesn't automatically make you a bad person. And doing something good doesn't automatically makes you a good person.
For example: Hitler liked dogs and treated his dog well. In no way whatsoever he stopped being a monster thanks to that. Your past counts. Your character counts. So its beyond me, why people think one good or bad action is enough to brand that person for life. (some actions, though, speak for themselves and are enough to brand someone).