You cannot be compelled in law to have your biometric card checked though by a private individual namely the barrier technician employed by the airport. So what's the point?
Seems to me that this is not about the access to a single airport per se but rather about identifying anyone BEFORE they ever get anywhere near an airport. Is it being applied to pilots to annoy them? No - I suspect it's more about the security people themselves, the baggage handlers et al. That's just my opinion though.
And the Police, Customs and Immigration staff have to have them too apparently, they are vetted in excess of anyone at the airport but will still need a card. Again, what's the point?
Why bother going through the main security point anyway - walk around the fence to the flying school at the back of most airports and walk through two unlocked doors to go airside.