As a fan of the shota genre myself I can say this. We don't read/watch/play shota because we like looking at the boy.
First of all, Speak for yourself because there are many shotacons just like lolicons who are in-fact attracted by the character themselves.
(All The Fallen says Hello!)
Second, I am also kind of like you, I don't like shota because of the character but because of the age-difference when they're fucking with a Milf. So, more like Shota x Milfs.
wishing it was us getting banged by the hot big milf
That's exactly the kind of mindset people fantasize in real life to defend female pedophiles:-
"The kid is lucky, wish I was that kid, the kid """
consented""" to it, the pedo woman is hot, you must be gay if you disagree".
I get you with all underage looking characters should not be in anything
First of all, you're objectively wrong as there's no harm done towards actual people by having depictions of a kid in fictional works.
Second, if you really think "having underage chars are wrong", you would not be playing this game, let alone trying to actively defend your shota fetish against loli fetish.
Otherwise, if we were to use this kind of logic in reality, Do you think you'd get away with saying "Oh, officer, I know I am in possession of CP but trust me, I am not attracted to the boy, I am only attracted to the boy fucking the adult and I am fantasizing as if I am the boy".
Lol, good luck with that excuse when you'll be behind bars completly missing the point that the act of a "kid getting statutory raped by an adult" is still present regardless of how you fantasize such acts. But be glad, you're just fantasizing pixels and not real people.