Cannabidiol is most definitely illegal in the US, too. That DixieX site you link to is just hemp oil products -- no psychoactives.
Also the amount of cannabinoids DixieX is citing is actually the minimum CBD content. They show their lab results on their Facebook page. The reason the don't cite the CBD content is because CBD is illegal, but hemp products are legal if the THC content is below a certain level. They're trying to play it off as a legal grey area and are taking a calculated risk.
And I don't mean 25-50% of the plant mass, I mean CBD will often make up 25-50% of an extract. (Wikipedia has my back with a 40% figure: http://en.wikipedia.org/wiki/Cannabidiol)
Fiat non-psychoactive, not fiat legal. It's definitely still illegal. But it's included on all the lists of non-psychoactive cannabinoids.
As for that journal article, it's behind a paywall even though it's from 1940 so I can't comment on it. But if you look at the menus for any dispensary that tests for both THC and CBD, you'll see that CBD is rarely a significant percentage of the cannabinoids, e.g.
This is why weed reduces one's risk of diabetes and also often helps obese people lose weight.[1] For what it's worth, you can now actually (supposedly) buy CBD (supposedly) legally online:
http://dixiex.com/
CBD is one of the more common non-psychoactive cannabinoids in marijuana, and it is responsible for many of the anti-inflammatory benefits. While more research is needed, lots of people are reporting the same sorts of benefits that this research is reporting, but without the obvious negative side effects of taking anti-biotics. (Whether there are negative effects of longterm CBD use is anyone's guess, but as far as I know nothing has been discovered so far.)
[1] http://blog.norml.org/2012/12/12/study-cannabis-associated-w...