Because this games main story was accessible for nigh on 10 years without that controller.
Generally that person would NOT buy other games that required quick repetitive button presses BECAUSE they understand their limitation.
On the flip side why are YOU so invested in keeping this "once in a playthrough" , sorry excuse for a challenge in the game as is? If it's so very trivial then why is it a problem to either remove the all or nothing req or maybe tone it down?