When the game is 6/29, the enemy Yasuo has 20 of their kills, but your team 1/4 vetoes...

correct, at the time he didn't even need that shit

yasuo's crit chance doesn't scale with his being fed nor does his windwall. Its just pure damage which falls off some lategame. Shut him down and you will have a chance if he actually took 20 of the enemy team's kills.

Its not just darius. People have done this whenever a single champ ate all the kills.

That's why the other 4 players knew better and voted against you who did not know this basic thing as evidenced by your failure to even suggest this could be possible in order to bury the thought.