My point is that using the Lenna image is a signal, just as you rightly point out so is my comment. I know exactly what the image is and is used for. But I also think it's sad that it's politically charged to say using a Playboy image in a literally objectifying fashion as a test-subject by a women who's requested we don't use it is bad.
It's not a sudden ban, it's been an issue since ~2015. Fun fact I learnt in this, Goyal is totally open to changing it (https://github.com/kovidgoyal/kitty/issues/661), it's simply no-one changed it. I'll see if I can, thanks for the correct call-out.