Is that a criticism? Yes, it is usually. It assumes that it’s not worth its place on the wall if it seems a “bit cartooney”. I’m not sure where one draws the line, ‘scuse the pun, but being cartooney was a criticism all those years ago when I was in art school. It’s a favourite of up-themsleves-art -tutors. I found it also prevalent amongst some art directors and designers, and I naturally avoided them as much as possible. Fortunately, they were in the minority.
Is there a retort to it. Perhaps: ” That’s a bit fine arty” might be one, or one could perhaps shorten that to ‘farty’.
Anyhow, it’s said the Leonardo did come cartoons, not sure if he would have approved of either the description but having seen them, I’m still trying to understand his jokes.