Me, also a dirkjohn fan: I have a psychological explanation for this-
Majority of the reason is that dirk jake is a ship that became canon yet lacked the on screen scenes (because Hussie sucks at writing romantic shit between two unsocialized teenagers obviously) and as a result, the fans do the opposite where they draw what the the canon lacked or things makes them forget what happened in canon.
-MLP fans draw horror since the media is already so cute.
-Breaking Bad fans draw cutesey meme stuff because the show is already so tragic.]
But they often lead to self indulgence total projection that results in mischaracterization and total disconnect to canon personalities. (The characters instead bacame self inserts rather than a homestuck ship.)
Meanwhile dirkjohn fans match the insanity of a theorist because they had little to nothing for the ship in canon in the case of interactions to begin with, but the charcters themselves are what the narrative depended on because in the start of their acts, they mirrored each other until the end so the inevitable result is the range of batshit insanity that heavily derives off canon symbolism, codependency and self indulgent cute stuff.
Also because dirkjohn falls under the famous character pairs like in other medias that have their relationship as the basis and is the entire reason why a show existed in the first place, sooooo lol.
Ex: Sonic x Shadow, Madoka x Homura, Shinji x Kaworu, Gon x Killua, Batman x Joker, Batman x Superman
Dirkjohn is so EVERYTHING and NOTHING they can fit into these characters' places but these characters cannot fit into their places.
End note: People who have no fucking canon content for their ships are genuinely insane. i.e: Dirkjohn shippers.