Piccolo caused buu to kill the entire human race and trapped himself goten and trunks inside the hyperbolic time chamber
Vegeta fought goku over some petty shit and caused buu to come out in the first place and refused to fuse with goku when he knew it was the only way to beat kid buu
Gohan he plays baseball and can catch a ball but not the potara and gets rocked because he didn't train one time by dabura that trunks made look like fodder
Gotenks let buu escape because of theatrics
Goku figured out that spopovich is sketchy and had the genius idea to fuse with gohan but gohan messed up the plan
Supreme kai he is a god and immortal but didn't even help
Chi chi slapped super buu and got killed
Krillin agreed with piccolos stupid plan
In short how the hell is the dumbest character in the show smarter then all of you combined in this arc