But in the end, it's the state of CA doing the screwing.
Being a FFL is complicated, to say the least, especially when you consider all the laws that you have to know and follow, including sales tax issues. That is the responsibility of the person who owns the business. The government is not going to teach a class for every business, nor for any business.
I don't think that they made it nebulous on purpose, that is just the way the government does things (elected idiots, etc.).
If a FFL does something because they don't understand what they are doing, then it is their fault. Yes, the laws are often hard to understand, as well as all the policies, but if you don't understand then you need to get help or not do it.
In this case, the firearm was not on the certified list and was not exempt, that is pretty clear. It is not the fault of the government if a FFL just attempts to find a way to get around things instead of understanding that the firearm can not be transferred. The bottom line is that if you don't know, don't do it and find out what the answer is.