How that information is shown to the ref is critical in the referee’s decision making. Show them a frozen frame of a ball hitting someone in the hand and their decision is immediately altered because of that.

It’s the same with red card situations. If you slow down the footage, freeze-frame it and show the worst possible angle that makes the challenge appear much worse than it actually is, then the referees decision can be altered significantly.

Mercy rule seems even worse than just losing badly ordinarily. Imagine getting beat so bad there’s a rule that exists just to stop you from getting beat even harder… That’s so much more embarrassing imo