It's volatile alright, but that's not the same thing as being able to push the market down with a retail-sized trade, let alone push it down a staggering 10%. And just because the market dropped 8%, doesn't mean the drop can be attributed to $2 million worth of Ether put up for sale on GDAX.

The daily trading volume is $300 million at last count. There's arbitrage happening across exchanges so the price on one exchange is not isolated from what's happening on others.