Regulation is requiring preemptive compliance with arbitrary rules (inevitably naively) intended to prevent an infraction (but never actually does), whereas criminalization is leaving people the hell alone so long as they don't do the bad thing, then punishing them after the fact if they do.
Regulation prevents nothing; no amount of paperwork ever stopped a single barrel of DDT from getting dumped. Worse, in practice regulations tend to protect the big offenders from prosecution, since, after all, they did file all those papers that the little guy couldn't afford to.