He's not a top, he's a mediocre mid, he's not a jungler or a support, and he's heavily outclassed as an adc. He doesn't fit in the meta, and he's useless since the ultimate nerf. He used to be really freakin' good, and then they crushed his ultimate and tooled around with his q and e and it killed him.
Also, don't take performance of a champion in a single pro circuit game as definitive. I have a feeling that Azure threw so CLG wouldn't disband (they made a lot of mistakes that they normally don't). But that's a conspiracy theory for another day.
Urgot was popular in S2 when ADCs were OP and picking Urgot basically meant you could ensure neither team had an ADC. After all the balance changes now, he's not really that great anymore.
My friend said he has a lot of fun playing Urgot, but can understand why he's not that common. He simply doesn't fill the role of an ADCarry, which is rather important to late-game teamfights and taking out turrets and inhibitors; like Kassadin, he's designed to shut down the enemy and then act as an extra body during teamfights.
Since he is an AD caster, not AA based.