I agree, it's unclear where the requirement to pay the fee begins and ends.
If I were to roll my own BT solution, using a generic 2.4G radio and my own software stack, it would make perfect sense to have to pay a licence fee for the technology, and go through a certification process to say "yes, this product that claims BT compliance really is BT compliant". The fee of $8k would be small change compared to the cost of developing such a solution anyway.
However, smaller volume manufacturers don't do that. They buy pre-assembled, pre-certified modules that include all the RF circuitry and software stack, and present a simple API over (say) a UART interface. These are relatively inexpensive (though nowhere near as cheap as the per-unit cost of a home grown solution), and their main selling points are the lack of need to develop a complete wireless solution or certify it. The compliance and certification requirements apply to the module; it's the module that's the BT product, not the device that incorporates it.
If there's now been a change in the rules which would indeed mean that a product incorporating an already-certified 3rd party module must now itself be certified as a whole, for a fee, then the OP is completely right to complain and so would I.