He is probably talking about K2, Spice, etc. This isn't really 'synthetic marijuana', those chemicals are not synthetic cannabinoids but naphthoylindole compounds. Media doesn't know what they are talking about, as usual. They just want to sensationalize/demonize whatever they can and this stuff is an easy target. It doesn't matter whether it is 'right'; it just doesn't matter.
Soon enough, some chemist in a far away lab will synthesize some other obscure psychoactive compound which someone else will find a way to market as some other novelty product. One not intended for human consumption, of course.
Until then the kids, probationers and curious psychonauts everywhere will scavenge for others ways to get their kicks and not have it appear on a drug test, or they'll all get drunk instead. Or maybe they'll just smoke ganja like they should. Any of that will do, as opposed to putting pressure on their politicians and local elected officials, or running for office themselves or in any other manner striving to bring about needed social change and release the stigma of getting 'high'.