Doesn't make sense

ok... so I have been thinking... growing Cannabis is illegal in the U.S. right? well, doesn't it make sense that when it is outside, it is growing itself, cultivating itself, propagating itself, naturally? the plants grow by themselves... right? This was sparked by an article about a guy that was hiking through a national forest with camping gear that ended up in Federal prison just for being within 5 miles of a huge crop when it was being raided (a doctor), when they couldn't find anyone else to put it on....

Not that I agree with the premise, but to play devil's advocate I am guessing the gov't considers there to be no such thing as "wild" cannabis. They figure they have destroyed it all, and if there is any growing it had to be planted by somebody. And that somebody is you is and me