You can die on this hill if you want to. Gimp has its reputation amongst the public, and it's not for it's user friendly UI. Maybe you like the jank, but that doesn't mean it's optimal.
Also, another thing open source projects need is feedback from the public. The UI being horrid is feedback, and just because you feel the need to white knight and feel personally offended by this feedback doesnt make the feedback invalid. You can complain about the phrasing used, but if you use that as reason to disregard the feedback or get defensive and accusatory towards the person (the "what have YOU done" bit was particularly irrelevant) then you're part of the problem regardless how much you feel you're the solution.