SOME one,
on SOME site,
speculated or knew that some companies say "not to be used for XYZ"
because there are federal regulations about products used for those purposes. Maybe only labelling regulations, but I think maybe licensing and record-keeping regulations as well.
Some experience with labeling requirements for software documents, indicates that, when you start to wander into the area of ITAR or EAR regulations, just figuring out WHAT wording is required can give you gray hairs or slow you down for weeksyou.
I can easily believe that it is cheaper to label something used by hobbyists, researchers and commercial growers "for hobby use only", than to figure out and comply with a forest of regulations.
Kind of like a vendor who "handles" liability issues by stating that safe use of the product requires NEVER OPENING THE CAN.