We have so many of them because the authors of all this legal stuff only concentrate on whatever single thing they are trying to regulate and don't consider "side effects" of their legislation
I think the way the law is written (and that's an important point, because I am not a lawyer), it says something to the effect that BP used in model rocket motors is exempt. Logically (a dangerous thing to try to apply to legal matters), an ejection charge, being "part" of the motor, is included under this exemption. I don't read any part of the law that limits this exemption only to BP that is manufactured as ejection charge material at the same time as the rest of the motor, so I presume (again, I am not a lawyer) that BP designed to be used for ejection charges in a model rocket, even when manufactured separately from the motor, are still exempt from legal control and regulation. I would expect this coverage to include BP as in the AeroTech supplies for the electronic fwd closure.
Speaking of gray areas, I think there is also some wiggle room regarding BP and government regulation in the case of make-your-own gunpowder. I have read through the laws over and over, and have talked this over with a lawyer, and I can't see any applicable controls....unless you try to remove it from your property, or transport it on public highways, etc, which puts you right back to scratch. Anyway, DIY BP usually does not perform as well as commercial stuff (at least, it takes a lot of work to get equivalent performance). But it sure would be nice if one of our govt agencies would copy the Canadians.
Next problem would be: would they write the new exemption to recognize the "real world" consideration that you will probably have to purchase, store, possibly transport, etc, a minimum of 1 pound of the stuff even if you only use 1 gram in your ejection charges.