Since we're talking about human remains in dog food, there's already likely a litany of felonies involved in turning a person into dog food. The regulators just like to regulate.
Theft is also forbidden by regulation, but thankfully I don't have to file daily reports yet to Theft-Prevention Agency listing all the things that I handled but not stolen today.
Theft is not forbidden by regulation, it's forbidden by laws.
What's the difference? Laws are written by legislators, i.e., the elected representatives. Regulations are written by agencies created and empowered by laws to oversee certain parts of the government/governmental functions.
Regulators work largely by requiring reports because most agencies don't have criminal enforcement powers, and thus can act only on the basis of what is (or isn't) reported...
The real difference is that theft is punishable under natural law regardless of what any regulators or legislators might say. There can be no consistent system which would permit theft while prohibiting a proportional punishment for it. If theft is permitted then enforced restitution (recovery of the stolen property) and punishment (fines) must also be permitted, because these are ultimately the same action.
Laws and regulations which are not merely codification of natural law ultimately come down to attempting to create rules which apply to some people and not others. Unfortunately, legislators and regulators get away with this all to often through a combination of good propaganda and willingness to employ unjustified force to achieve their goals.
Greed doesn't listen to reason.