I wouldn't call bath salts are an epidemic. An epidemic would imply a large usage. while most people I have talked to HATE synthetic cannabinoids. The reason their use is prominent is that marijuana can be difficult to obtain and these synthetic cannabinoids do not show up on standard drug tests. The usage of such an unresearched drug is stupid to say the least, these do not have a safety profile and it is unknown if they break down into toxic byproducts.
The reason these drugs are legal is because they are analogs and are only considered illegal if intended for human consumption via the federal analog act.
Anyway, these people probably went countless nights without sleep when they committed these atrocious acts. While the drugs effects may amplify their behavior, not sleeping for weeks would probably turn all of us into weirdos as well.
This is the same type of yellow journalism that the drug warriors have been preaching for years. They find an isolated case and they blow it out of proportion and attribute it solely to the drug and act as if the person was completely normal before the drug usage.