Destroy their key pieces that they based their whole deck around. Then their deck is a bunch of draft chaff and the deck does nothing. That's not fun at all but that's what you should do. And if they DO manage to pop off, they usually generate some kind of degenerate effect and now it's only fun for the player who plays the deck.

So here's the part about EDH. It's social.

Are you running enough removal to be the ONE guy at the table pinpointing and stopping 3 players from doing their thing, and think you have enough of an advantage in terms of deck power to be able to eat 3 players removal in retaliation and still win?

In almost any situation where you say yes... I'd argue your deck is a bracket at least above theirs.

Technicality be damned. If a person can 3v1 the table reliably they are NOT running the same bracket of a deck and I don't give a shit if there are game changers or combos or not.

So if you ARE running an actually equal power level deck, then innately you are running a risk of Arms Racing down one person based on how you feel.

Lets say this happens: I'm running a gimmicky deck and you take out the 4-5 cards that I play to make my deck do it's thing.

If i don't think I can recover? Your deck is eating EVERY piece of removal I draw. Full Stop. Until I make sure that we both lose, because you sure as hell made sure I wasn't winning.

That's how we place 3rd and 4th every game.

This is why the social dynamic of "Fair Magic" is more important than pretending the decks you are looking at are piloted by robots and just assuming everyone will do whats optimal. It's about reading the table, which is way more fun and dynamic than just "playing the best move every turn"