the only excuse I see from people who think it's okay to give fanfic writers unsolicited criticism is "if writers can't handle criticism, they should not be posting their works online" and tbh I think it's such a weak, pathetic excuse to be entitled.
someone not wanting unsolicited criticism on something they do for themself — for fun, as a form of self-care — out of love and passion has nothing to do with whether or not they can handle criticism. because we're not talking about a job they get paid to do. we're talking about a damn fanfiction. a hobby. something writers do in their free time as their source of comfort and getaway.
it's their art. not yours. it can be whatever and however an author wants it to be.
instead of trying to justify your action by gaslighting writers — whose works you read for free — that they "should be able to handle unsolicited criticism", ask yourself why you feel the need to go to someone's fic, read it, and then complain about things you don't like when you can always quietly leave if you don't have anything nice to say.
"can fanfic writers handle unsolicited criticism?" "can you learn basic manners and how not to be entitled?"
either respect artists or shut the fuck up forever.
omgitskaii