I wonder why the anime girl is received so badly. Is it because it's seen as childish? Is it bad because it confuses people (i.e. don't do this because other don't do this)?
Thinking about it logically, putting some "serious" banner there would just make everything a bit more grey and boring and would make no functional difference. So why is it disliked so much?
Why? It has sexual connotations, and it involves someone under the age of consent. As wikipedia puts it: "In a 2010 critique of the manga series Loveless, the feminist writer T. A. Noonan argued that, in Japanese culture, catgirl characteristics have a similar role to that of the Playboy Bunny in western culture, serving as a fetishization of youthful innocence."
Clearly you proved that. What has sexual connotations is wildly subjective and plucking the opinion of one author/poet's critique from 15 years ago doesn't make it fact today.
It's about perception and feelings. If anime cat girls have sexual connotations (for a large enough group), that's the way it is. That critique didn't come out of thin air, and its age is hardly relevant. The association has been established. If you use a symbol that has a certain association, you shouldn't be surprised if people react to that association when they encounter that symbol.
There's nothing wrong with "subjective", by the way. You seem to think it discredits something (can't say what exactly), but this topic is subjective. It's not about logic (as if anything outside maths ever is).
Thinking about it logically, putting some "serious" banner there would just make everything a bit more grey and boring and would make no functional difference. So why is it disliked so much?