airbourne,
the only reason anyone would want to buy food on an FR flight is because they are sick of the gouging in the pax areas at DUB - one squillion quid for an orange juice [bottled] and sambo [plastic] and no avgas used to transport it
If you want to eat on most forms of transport it's pretty expensive and not very satisfying, as users of Irish Rail can attest.
FR state that if you use a debit card, you don't pay the fee - haven't tried at as I prefer visa but feel free to take a look.
If they "make money" on the taxes, then I'm sure EI et al can refer them to the director of consumer affairs, or you can do so yourself!