The gold market can be manipulated as most people never take physical delivery of gold. There's no mechanism to audit everyone's holdings. Additionally, I'm of the opinion volatility will decrease as bitcoin matures. Do you really expect a currency bootstrapped from the ground up to not be volatile in its uptake?

We'll see if you're singing the same tune when you're finally confronted with the certain depreciation of your USD holdings. (Will you still reject bitcoin when USD is depreciating at a rate of 5% per year?)