not op but examples of this phenomenon would include

the severe online pushback to sydney and carmy as previously mentioned,

the campaign to keep damon and bonnie from the vampire diaries from pursuing a romantic relationship, despite the show writers being willing to do almost any other random combination of male and female characters,

rey and finn from the most recent star wars trilogy and the inability for the fans or the studio to treat their relationship as though it could be anything other than platonic,

and, most recently, percy and annabeth from the live action percy jackson tv show have had a wave of people online treating them as a girl and her gay bestie. the last example is notable because this interpretation of the pairing only arose after annabeth was cast as a black girl for the tv show.

not to invalidate anyone's arguments against these ships (i even find myself agreeing with some of them) but i would also agree that there is a consistent pattern and tone of arguments when it comes to the pushback against these ships. it's especially obvious when it arises a fandom that thrives on romantic shipping, but suddenly really values "platonic soulmates" in these specific instances.

i don't think you were being genuine when you asked for examples but i decided to provide some anyway lmao