Why does citadel’s boss require ALL players to vote to start?

I understand not wanting to force feed someone into doing an Easter egg; some people just want to chill out and not watch a YouTube video in order to play a game.

But we're at the point where we have the final boss vote started and 3 out of the 4 people in the match want to do the fight. One singular person in the match after roughly 45 minutes of setting it up is refusing to vote in favor because "they don't want to do the boss".

I understand it's a dick move if 1 person is trying to make the rest of the lobby vote for it if they don't want to, but why should a singular person be allowed to sandbag the entire lobby?

Why isn't it like an extract vote where it only requires majority to start?