
i agree with your observation.
people here who are referring to seonhwa as a twink ARE using it derogatorily.
example sentences that have been used (comments from a couple days ago, because that's when I took notice of them) include: "my hatred for manhwa twinks was so validated here" "get lost twinkle twinkle little star" "twink removal operation start!"
like, you don't ever see bottoms being referred to as twinks in other series on this website. but somehow now that there's an unlikeable character who can fit the meaning of twink, he's referred to as twink almost exclusively?? and always in a rude way?? how would anyone else interpret the constant use of twink here, if it isn't meant to be an insult.
also "twink is not a slur at all so therefore it's never going to be derogatory". monkey isn't a slur either but if a person of colour was called a monkey to dehumanise them, that's clearly racism. context matters, and in this case, twink IS used in an insulting way and in a derogatory way

What you're saying makes no sense. Reading a gay story doesn't suddenly give you a right to use terms for the LGBTQ+ community. This is the issue I have with straight people who read these stories, you guys don't take the time to actually appreciate queer love or respect queer people. You just fetishise us

in simple terms: the issue here isn't whether or not twink is a slur. this isn't a binary checklist that goes "twink is a slur and therefore people using it should be ashamed unless they're gay themselves / twink isn't a slur and therefore anyone and their grandpa can use it".
the issue here is that some people in the comments are using twink as an insult. there's an unlikeable character in this series that can be described with a word that is exclusively associated with the (real life male) gay community. and people are using that word to bash this unlikeable character - when in other series, where the slim male character is likeable, the word "bottom" or "uke" is used instead.
so what does this all mean? it means, when someone is calling you out for homophobic behaviour, instead of going on the defensive by saying "actually twink isn't a slur and therefore no one is being insulted here" and using textbook definitions to win your argument (textbook definitions don't ever have the required context!), try instead: reflect on the context and think about why that person is interpreting your behaviour as being homophobic
As a woman what gave you the audacity to use the word twink in such a derogatory way? I swear some of you read BL and lose common sense. You realise you are acting homophobic af right?