It was a serious question. I mean, I'm not completely sold on it but the argument in favour definitely makes sense. I was just interested in the argument against, and assumed you must have one.
It definitely doesn't make sense, not for anyone who's given it longer than 2 minutes thought.
So let me paint a scenario right here for you what you and that phony is endorsing....
In our next league game at Brighton Welbeck goes studs up on Szobo's shin......Szobo has to be subbed off to injury. We get a pen and Mo misses it. Welbeck stays on the pitch of course because of this bullshit new rule, goes on to score the winning goal and also because of this shitty new rule has no further punishment i.e is not suspended for the next 3 games.
Is this what you want in the game? Because I can assure you we'd have plenty like it.
In any case you can't just go abolishing old rules that've been in place since the very start because referee's are subjective on what is or isn't a red card, the subjectivity will still be there and you'll still have thousands of fans in uproar because they've lost a game over a dubious pen that was never a red card worthy foul in the first place. You're essentially going from 1 extreme idea to the other.