The guy didn't take LSD, LSD would not cause anyone to behave in such a way. My first guess was that it was PCP, but it turns out he was high on bath salts.
As to why more people don't start eating people's faces off is because the chance of you reacting to a drug like this guy did is extremely unlikely and based on the person's mental stability in the first place more so than 'just' the drug. Obviously, repeated use of certain drugs will essentially wear down any person's emotional stability or even sanity, though even then the vast majority would not respond like this.
Kids, (some) drugs are bad, mmmkay.