“why do some fanfic writers write non-con fics when it’s for the sake of smut and romanticized?”
some victims and survivors use dark fiction to cope and heal from their trauma, because in their fics, they are in control of what happens. they can turn the table and turn what happens into something that’s not traumatizing. and they can do that because they don’t owe you anything.
it’s a kink to some people, even though they were never victims. people can enjoy it and find it hot because at the end of the day it’s just a fantasy. it’s not real. they don’t owe you anything.
it’s cathartic and/or therapeutic to some to see their favorite fictional characters suffer. that’s why whump is such a popular trope; people love putting their fictional little guys through hell. non-con is a part of whump. and these people don’t owe you anything.
fanfic writers can write whatever they want, however they want. they don’t owe you anything.
I also suggest that you look up cnc kink and why so many couples are into it.