How is acceptable to not condemn it once he is informed of it? He defends the guy saying he's a great guy instead of making clear it isn't ok to murder political opponents. You're not even trying anymore.
Because Trump would have to make the assumption that the media report is true instead of independently verifying it first and is put into the uncomfortable position of bashing a surrogate without verifying the facts.
Look we all have to agree that a candidate is not responsible for the stupid s**t their surrogates say.