Of course, UA responded as it did. If the EU nanny rules are ultimately interpreted so as to require compensation for MX where all required maintenance was done, that is, the MX was unforseen and unforseeable and therefore not subject to compensation, TATL fares will rise by a good 20%.

You can expect the carriers, esp. the USA-based carriers, to fight this to the end of time.

OP has two choices: 1) take what's been offered and enjoy it; or 2) fight to the end of time and maybe see a few Eur which by then won't by a cup of coffee or lose and buy OP's own coffee.

The EU rules are a prime example of the law of unintended consequences.