* The touting is not illegal in and of itself - most touters are even including disclosures about their own activities (it is, however, one of the authors' recommendations to nail some of them for breach of CAN-SPAM)
* These are not NASDAQ or NYSE stocks, and don't behave anything like that. Those are unknown, small stocks with very small trading volumes. The touter and the people he is fooling are often making up much of the trading activity in the period around the touting. They are also "penny" stocks, which "tick" in pretty large increments (percentagewise).
* Consequently, the only people likely to benefit or hurt are the touters and the people who bought into their messages (i.e. no "innocent bystanders")
It is unclear to me that this is a problem for the regulators, at least not from the point of view of protecting the "victims". After all, people are free to make bad choices and these are not fraud cases (the authors note that this is "investor irrationality"). There is, however, a negative impact on everyone else, because this sustains high spam levels. Probably the "CAN-SPAM direction" is the regulatory way to go, rather than something more specific related to touting of financial assets.
There is an old saying that goes caveat emptor - Let the Buyer Beware.