The real reason everyone makes fun of Dicks Discowing outfit is because he's the only one that can somehow pull it off

Every superhero and vigilante has has a costume like that at some point, something daring or a bit ridiculous that in hindsight that they just couldn't make work for whatever reason. Nightwing? The pretty motherfucker not only made it work, he slayed in that outfit. It looks ridiculous by itself on display in the batcave but not when Nightwing puts it on

The only reason Dick doesn't know this is because all his siblings have collectively gaslit him into thinking that it's his worst costume to date.