Hrm. In my view, that's still being attracted to the cartoon, not the person. If you paste somebody's face on a blow-up doll and have sex with that, you still haven't had sex with the person. That you confuse your fantasy character with a real person doesn't make the fantasy relationship more real.

Also: continuing to display attraction signals to somebody who isn't interested in you? That comes across as creepy. As would fantasizing about someone you know who doesn't find you attractive. For your sake, I hope they don't find out.

If the author's black-and-white statement still is bothering you, go ahead and insert some nuance. E.g., "normally" or "for non-creepy people".