The general belief of the cause of gyno (in the medical field) as I understand it (and as how its explained in the first article you posted), is not necessarily an imbalance of any sort, but simply a excess of estrogen and an lack of androgens (like dht).
We know as gear heads you can be running 2+ grams of gear, and have MANY more androgens as opposed to estrogen (or any other unwanted hormones) and still get gyno. I personally think its just a matter of high estrogen, how much estrogen does it take? Depends on the person.
Gyno happens to ALOT of guys naturally and has been happening for centuries. It just so happens that teenagers use drugs doesn't mean that is to blame, it seems to me that the finger is just being pointed at drugs.
Unless there is a study performed on kids who did not have gyno and had healthy hormone levels, then are given drugs, that show that they cause a hormone in balance followed by gyno, then upon cessation of the drugs the gyno ceases and the individuals hormones return to normal, you simply cannot say, from a scientific standpoint that weed, amphetamines, or any other illicit drug listed causes gyno without a study actual showing this data.