Why are ADC's allowed to still build Black Cleaver?

Correct me if im wrong but Miss fortunes ult Shreds through armor cause of and it doesnt seem fair that this item is better on ADC's than most Melee champs due to their weaknesses and such So some ideas that some others might have said already but im not aware of

1. Make the stacks double for Range champs (I believe its 6 stacks for the full %) That way if adc's will build this, they're forced to build Attack Speed items like Phantom dancer or Runnans Hurricane to get the full effect of the cleaver
2. Make Black Cleaver melee only (Easy one, simplier to balance for Melee champs?)
3. Like with recent changes like Caitlyn and Next Kennen, they removed multiple stacks from using hurricane as it stacked e.g Headshot really quick. Make it so Black Cleaver doesnt stack on Certian abiltities/Passives or whatnot

I know im not big on the boards or popular here, but for adcs to be decently tanky and deal more damage post mid game than most Melee or normal AD carries that build crit an takes time to deal damage? Doesnt seem fair to me

but this post is my opinion on it, as a Darius main myself, i wouldnt want Black Cleaver to get nerfs cause of ADC Abusers (Cough though they fixed that item)

Thanks for reading!