You don't know what you're talking about,imo.
Amumu -> burst damage
Where? Only if you have an heavy aa comp,in which his E gets practically no CD,but in that case,you would kill him with % armor pen and lifesteal. Also,Q it's his only mobility spell,dodge that (or go away when he uses it on minions) and you're good to go.
Olaf -> ridicoulus damage
Did the olaf build full AD? If so,then you can kill him with one combo. If not,you're lying. He does pure damage on his E,but he loses health doing so,has a good CD and wastes time with the animation AND it scales off of his AD,both in damage and cost,so he can't be doing both tank and damage threats. I play Olaf. I know. What stops me? Adcs who know how to play or good supports. Or 1-shot mages like syndra. Why? Cause when he ults and avoids all CC,he loses A LOT of armor and magic resistance,and his"mobility" stays up for 1 SECOND if he's going TOWARDS an enemy,so it can't be used to escape unless you want to avoid CC.
Also,his Q it's easy to avoid,especially if he's a player who trows always max distance.
Fizz -> CC
He has only his shark. I do perma-ban him cause,being an assassn with invulnerability,i prefer avoiding him,but think before writing.
Nasus -> 1-shotting
Only ADCs who don't move out of the way get that treatment. All others are getting 3 to 4 Q in the head before dying,if they don't duel him in his E. Being a Juggernaut,CC him while the ADC keeps hitting me STAYING AWAY FROM HIM. NEVER STAND NEAR THE DOG'S MOUTH.
Also the slow is 99%. Seriously,think and inform yourself.
Cho
Yeah,thisi s kind of true,a bit like fizz,but you have all early game to destroy his possibility to get CS,destroying his possibility of getting gold,destroying his possibility to get items and get tanky. Like all other juggernauts and damage based tanks,in late game he gets insanely good if played well. His downside? SLOW AS FUCK,EVEN MORE THAN NASUS OR URGOT,AND HE HAS NO GAP CLOSER,SO JUST WALK AWAY AND AVOID HIS Q and you won't die.
"But how to avoid his 1.5k true damage point and click ult if i'm an adc qith only 1.3k hp? it's a oneshot!" Don't go alone and have the reaction to go away when he flashes. So don't get immobiles like Ashe or Jhin.
Now,I know you are/were salty,but going on gameplay boards isn't a good way to get away from the feeling. If you wanna de-salt,better listen to music you like,or talk with friends/people you can trust about what your problems with those champs are. I was aggressive,just because i hate people salting on champs which are actually balanced. If it wasn't filled with salty rage,i wouldn't have been so aggressive in my response,so,hopeful that i have actually helped you and not only salted you even more,good evening and good luck next time.