As I pointed out they are not "genetically manipulated" except to the extent that humans have always bred stuff they raised. Reread points 2 & 3 on that count. Of course people are going to cross-breed something they want to consume. That's what we do.
As for high-THC outdoor weed, I've encountered it plenty. An old dealer used to grow the stuff in fields he scattered around the state, with minimal supervision. Now that MA legalized, I'm doing my own outdoor experiment, so perhaps I'll check back in in a few months. In point of fact, it's actually much easier to grow good weed outside. The only reason all the indoor growing techniques sprang up is illegality.
Further, the claims about weed being only a few percent THC in the past are generally derived from old studies. The problem with old studies is that the feds had to supply the weed to be studied, and they deliberately supplied garbage weed. Properly grown weed has always been significantly stronger, whether indoor or outdoor.
yea the old studies would say todays marijuana was up to 30 times stronger than the old stuff.. but newer studies that have been done since Colorado has legalized it show there is certainly an increased THC potency
.. but also many strains have almost no CBD which makes it less useful for medical marijuana.
as for genetically modified well....
US Patent Pending for Genetically Modified Marijuana > Hawaii Free Press
Also Monsanto ( of course the GMO king is jumping in to this ) has created a genetically modified marijuana
We're overlooking the most important factor in this: the vast vast vast majority of users are not Willie Nelson or Snoop Dog. They do not roll huge joints of whatever they happen to have and smoke them. They take a few puffs as they desire. If the weed is stronger, they actually smoke less of it.
The whole thing is misdirection by someone who quite obviously has no experience and very little knowledge of it. That's unfortunate, because it's also why the War on Drugs has gone on for so long.