The hadith does not imply that ones should dare to commit sine. The sinful was forgiven by the mercy of allah,but it is not necessary that every sinful person be treated in the same way.as principle.there is a punishment for every sin. No does it mean that people should not be stopped from doing evils and wrongs.in qur'an and hadith there are hundreds of places where are commads to stop people from doing evil:and warnings against not forbidding evil.however,the messsage to be conveyed is that a pious person should neither rely on his own good deeds nor pass judgements on the sinful nor consider him self to be superior to them.