It's been tested somewhat (interestingly, in a trademark case which rested on whether the infringed trademark was for a legal product) and it has succeeded at the Circuit Court level. AK Futures LLC v. Boyd Street Distro, LLC, 9th Cir. No. 2-56113 (May 19, 2022):
Importantly, the only statutory metric for distinguishing controlled marijuana from legal hemp is the delta-9 THC concentration level. In addition, the definition extends beyond just the plant to “all derivatives, extracts, [and] cannabinoids.” 7 U.S.C. § 1639o(1). The use of “all” indicates a sweeping statutory reach. See Lambright v. Ryan, 698 F.3d 808, 817 (9th Cir. 2012) (“The common meaning of the word ‘all’ is ‘the whole amount, quantity, or extent of; as much as possible’ . . . .” (quoting All, Merriam-Webster (online ed., visited Oct. 4, 2012))). This seemingly extends to downstream products and substances, so long as their delta-9 THC concentration does not exceed the statutory threshold.
Of course, as this was on an appeal of a denial of a preliminary injunction, the ruling is framed in likelihood of success rather than absolute terms, but its a pretty strong negative indicator for your argument that this is a clearly incorrect interpretation that no court would take seriously, since both the District Court and the Circuit Court very much took it seriously.
This is the key. Who will ever bring this in front of a judge? The "anti-weed" lobby has all but ceased to exist. Which leaves basically a small handful of deep red state attorney generals that would even have the standing to be able to attempt it.
And which side do you think has the funding (and incentive) to defend it all the way to the supreme court?
The floodgates have opened, and they're never going back. There's simply too much money and momentum behind it. Even the conservatives are on board at this point now that they've seen the tax revenues.
Apparently, an accused trademark violator, in the hopes of proving that, as it was not in legal use in trade, the trademark they are accused of violating was not valid in the first place.
For example, Florida recently was about to pass a state law limiting the total amount of THC in each individual edible, which would have killed the "legal D9 THC" market. They apparently got huge pushback from producers/consumers in the state and dropped any limits: https://floridaphoenix.com/blog/florida-senate-approves-hemp...
Edit: BTW, though, that link from Matt Zorn was great, thanks for posting.
They're swapping out legacy industry worker addiction to opioid and alcohol for cannabis.
Socially, it's done a lot of good in those places.
Here's a commentary by drug policy litigator Matt Zorn: https://ondrugs.substack.com/p/delta-9-thc-gummies