"Retarded" is a word I would avoid, but yeah, fans behind a character are typically going to be passionate about them. You could make a case for Hinata surpassing Neji, but Sakura is the strongest kunoichi. It doesn't make them delusional to think or argue otherwise, just more your typical passionate fan.
I do disagree with the KibaHina part, as NH did interact, and Kiba teased NH himself, I don't think "acknowledging" those feelings is much of an argument for an entirely different pairing, and Kiba does not really emulate the features that Hinata found endearing in Naruto beyond being more arrogant really.
Did Hinata do something in any of the Boruto Material that made her surpass Neji ? From what I've seen in the manga and "The Last" she clearly didn't.
You can be a passionate fan yet understand the reality of a character's strength. Alot of Hinata fans I've seen don't understand that reality and just want to overhype their fav to ridiculous extremes.
For KibaHina part, you can argue that Kiba began to "emulate the features that Hinata found endearing about Naruto" (which was mainly the idea of never giving up and believing in oneself) after his chunnin exams loss. I do think Kiba acknowledging Hinata's feelings (e.g. Kiba teasing Naruto about Hinata) can be used to justify the pairing because Naruto, on the other hand, didn't view Hinata's feelings as anything other than platonic until the movie.
Kiba, at least, understood, and they were closer anyway. Hinata's feelings could've matured where she got over Naruto, imo.