Where does notion of demon slayer only having sad backstories for demons even come from?

Whenever I see people are always like "oh here we go again with sad backstories for demons" and I'm likeee at how many times this shit is even applicable?

Kaigaku doesn't have any "sad" backstory, he is legit a traitor for putting Gyomei in jail and causing Zenitsu's master to commit suicide.

Gyokko was a highly psychopathic human who killed a child and put him in pot as a "painting", Hatengu is a legit loser that even Tanjiro didn't care to listen about his backstory.

Nakime is a murderer when she was human, Douma is highly sadistic and nihilistic probably the most terrifying upper moon, Kokoshibo is classic the one living under the shadow of strongest trope. Muzan is Muzan and i genuinely feel bad for you if you sympathize with him.

So... If I count on my fingerprints the ONLY upper moons who you can sympathize with are Daki + Gyutaro and Akaza. That's like 3 upper moons out of 9 upper moons + Muzan.

So majority of demons are not created to be likable so the notion itself is false.