[DiogenesKynikos]

Comparing oneself to Galileo is generally viewed as a sign of crackpotery, especially if it's used as a response to legitimate criticism.

> Just that the fact that there are some unexplained missing piece does not mean one should reject it so quickly.

It's not just one missing piece. It's a whole series of basic properties of the observed universe. Most MOND theories are tailored to match one particular observation, but fail to match everything else. Until there's a MOND theory that matches a basic set of observations (like CMB anisotropies and the large-scale structure of the Universe, the ratios of abundances of the light elements, weak lensing measurements, etc.), MOND is simply uninteresting to most astrophysicists.