Tsuihou Sareta Renkinjutsushi-san, Saikyou no Dungeon wo Tsukurimasen ka? - Vol. 1 Ch. 5

[MangaDex]

 

[fucknvampire]

Don't make a girl cry, GOD I hate when characters say stupid shit like that. Shut up, spirit. Who cares if some brat cries? You have absolutely no right to say that when you're a being that basically feasts on dead people. You know what's really rude? Her shoving her ideals onto him when she was absolutely worthless when that bastard Allen kicked him out. It doesn't matter what you want, Mary, it's HIS life. Don't say stupid naive hypocritical crap again, tit for brains.

 

[Seraphus]

MC:
Hero-boi is self-centered, sociopathic, and evil, so he needed to get rid of me. He's definitely not evil, though; I'd have to ignore how bad he is if I said it out loud, after all.

Why do manga authors do this? It seems to be a staple of "kicked-out of party" stories, and I really do not understand why it is so common.
Is there some culture that encourages sociopathy and sells sane people down the river, and they're just... wait...
Is it my mistake to think that other cultures are different from mine, maybe...? I figured that since this kind of bullshit ends at high school where I live, that other cultures just didnt have this, actually.

Either way, I fucking hate this trope.