I agree the taxes shouldn't be collected free of charge (but they are). These are fixed costs imposed by governments which are being passed on to the consumer.
The remainder: Passenger Service Charge/Airport tax (Tax? I didn't know airports could impose taxes); Aviation Insurance Levy;
PRM Levy; Flight Delay/Cancellation Levy (EU261); ETS (Emission Trading Scheme) Levy; Administration Fee are all charges imposed by FR. These are not charges imposed by governments, airports or other third parties which are then passed on to the consumer. The amounts are determined by FR and (excluding the PSC) are at least £14.74/€14.74 per flight.
It's ironic that Mr O'Leary, who is well known crowing "No Fuel Surcharges" goes along with all of these surcharges - which have exactly the same purpose. They should be included in the fare, not added as extras (as should fuel surcharges)
Oh, and they do apply an interesting £/€ rate. (BSR is currently 0.85)
They are not the only ones, I'm not picking on just them - but they do offer one of the better targets.