Yes, I believe it is fair that the man who confessed on Youtube to killing a man while driving drunk received a 6.5 years in prison sentence, because he did the crime. It does not matter how he was found out. He confessed that he did the crime, so he should do the time.
The man in question deserves no sympathy. He killed a man and he should be held to account. He also thumbed his nose at the legal system, and he should never have done that. His confession should have been to a judge and the family of his victim. It should not be to the faceless Internet at large.