I have no idea either. Sometimes there are such teams that don't work out for whatever reason.
If in this particular case the tank had been one of the DDs and died constantly, well, fine with me.
But as a tank you play a key role. Tank and healer are roles that carry a lot of responsibility. It's okay if someone's new, but it's not okay if someone's unwilling to learn, or too stubborn, or stoned/drunk.

Now, why the vote didn't pass, I do not know.