I love this topic which the only South Park kids to have the world's worst parents are:
Butters - his parents, Stephen and Linda are crappy abusive jerks that punish him for no reason like the Butt-heads episode,selling him to Paris Hilton,Imaginationland part 3 episode,& tried to kill him in Butters' own episode which I've always hated them

which Butters is cute/innocent & my most favorite character ever that I feel sorry for.
Stan Marsh - his father Randy Marsh was a pretty stupid lousy father who was hilarious for doing really stupid things like the Bloody Mary episode, baseball episode, mega pooping episode, the N-Bomb episode

& which him & his wife Sharon having a daughter named Shelly who's a mega abusive jerk on Stan which they ignore.
Kyle - his mother Sheila was a bad crappy jerk mother by giving the kids chicken pox,banning Terrance & Phillip in that one episode, & bothering the poor school nurse with the dead phaetus.
Mark and Rebecca the homeschool kids - their father was so annoying by being such a jerk on the boys' parents, but I'm glad he got duct taped to the flagpole

since he annoyed me.