In the vast, infinitely complex world of the international economy, what difference can one man really make? Even billionaires don't have enough cash to really make a difference -- if Bill Gates went nuts and tried to crash the stock market somehow, other billionaires, banks and world governments would be there to stop him.
Yet throughout history there have been times when everything came together just right for one single person to ruin everyone's shit.
It' s a bum rap for Soros, the real culprit is who ever was setting monetary policy (I can't figure out exactly is responsible for this in England, it's a sticky wicket with a lot of players in the game.). Short selling gets a bum rap, it's very useful for discovering the real market clearing price of a commodity or equity. Soros just understood that the pound wasn't worth what England was trying to force it to be valued at, if the government wasn't involved in trying to artificially support the currency they wouldn't have put themselves in that spot.