This is probably similar to the debate between management and engineers at Intel. As an outside observer who has never been near CPU design let alone process engineering - TSMC's nomenclature smacks of moving the goal post to claim a win. Despite the reality that from a process engineering standpoint decoupling the "transistor size" from the production node is an improvement and allowed TSMC to ship a technically superior process.
And also does it actually matter. It ultimately refers to some improved denser semiconductor process which is what the customer is buying.
These processes are not exactly standardised either it would be a major undertaking to take an architecture from TSMC 7nm to 5nm let alone moving from TSMC to Samsung, Global Foundaries or if at all possible Intel.
That's your bias. To a process engineer the parameter that matters is what wavelength you are blasting the mask with and what size a feature it can create.