The attraction to a character develops through the actions and personality of a character, with the visual appeal absolutely playing a part but not being the decisive factor in the slightest. Many cartoon characters are just basic geometric shapes, but their personality makes them (erotically) appealing to certain individuals. By your logic every cartoon, every anime, and every live action movie starring beautiful girls would have unanimous support. This clearly is not the case. You would see more HOT Characters getting more NSFW art.
I think non-anime fans have a very hard with the concept and the math is off with them thinking>I'm attracted to real under 18 = I want to fuck characters only under 18
When most of the time it's many develop though actions and personality of a character a non or sexual crush on the character, this does not mean they are attracted to real children and teenagers.
The other problem is I think it stems from culture, Women devolp feelings mostly tho actions and words vs men who find sex appeal first and in 2020 it is not always the case for many men and coming from someone who married his best friend I was not attracted to her on first site. Hell who knows maybe most of this generations are still somewhat children with there "puppy-love teenager like crush's" on cartoon characters.
Believe me I'm not deigning there are always going to be a sick pedo using the NSFW art as a cope but that's only 2% of the porn fandom.