If you're going to play the safety card you should charge every single person caught foraging for edible wild mushrooms. Every year I hear reports of people dying from eating the wrong mushroom.
You should be aware that these laws do not serve as guideposts but as tools of oppression. I mean that literally and not as libertarian hyperbole. If you want citations I can do the needful for the same.
The opioid epidemic has been well documented as being created by Purdue Pharma, et al. It's also clear by now that treating a medical issue as a crime only makes things tragically worse.
But this all goes back to a central question: should the state have authority over your mind? If not, why are these laws on the books?
Preventing graffiti at a state or national park doesn't make us safe either. We still prosecute those who graffiti.
Poaching rabbits doesn't make us safer. It's also illegal.
In this case, he did break the law by picking mushrooms where it was specifically prohibited, and it would be reasonable to cite him for that fact.
But it wasn't about theft, it was about the fact that he wanted to ingest a compound which would alter his state of consciousness. That should not be a crime.
I list more examples at https://news.ycombinator.com/item?id=15052587 .
The U.S. Constitution might be a good place to start talking about what laws should do. It says, "...form a more perfect Union, establish Justice, insure domestic Tranquility, provide for the common defense, promote the general Welfare, and secure the Blessings of Liberty to ourselves and our Posterity..."
The 10th amendment says: "The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people."
It wasn't not written to be a general-purpose commentary about what laws should be.
Remember, it was also written to allow people to be property. It also says that there is freedom of religion, but that was at the federal level. Some states had official state churches for a few decades more.