Do you guys seriously believe there is significant commerce in Bitcoin besides drugs and gambling?
Some. Remember how thin the order books are, too, in relation to the total number of BTCs held. Less than .1% of all Bitcoins being dumped by a retailer has a substantial impact on the price. Your argument isn't illogical, but it is incomplete.
So by your own logic is it not fair to say that the retailers probably aren't selling their coins into the open market and immediately after getting them. After all it has a substantial impact on price.