Did you serve in the army, kid?
If you're talking about dictatorship and one-man judging, then there's a much higher chance of corruption in judging.
A judge is a very vulnerable figure; if they get involved in something like that, players will simply stop signing up for Tournaments, and at best, they'll all leave the current one immediately.
Besides, in this case, to embody the principle of "the law is the same for everyone," the judge must have a strong character; otherwise, even if they catch someone cheating, they won't be able to penalize them.
Remember Vitalik's case; Neo initially had a very weak position – he was not only the judge but also the injured party, Vitalik's opponent in the final. That's where there was plenty of room for gossip and speculation with almost any decision.
However, he handled the situation with dignity. I'm even afraid to imagine what the Arbitration Committee would have done... Vitalik had a very strong support group, and the situation was also not 100% clear.