To be clear on something, that the Empire has no control over what occurs on the SCC markets is something agreed with even before it was restated in the MIO actor's most recent post - otherwise, wouldn't the Empire surely ban the trading of Khumaaks, pornograhic holoreels, and other unwelcome items in its territory? As an extension of that, I entirely agree that, with the information we have been given, the SCC represents a colossal loophole to the otherwise tightly-controlled Amarr economy.
It is that a loophole of this magnitude exists in the Empire's economy that surprises me. To quote another bit of the Amarr Trade registry description, "The Amarr government seeks to control as many aspects of the daily life of its citizens". So, it's trying to control... except where it doesn't appear to give a hoot?
I mean, wouldn't a loophole this huge be abused colossally? Holders could use it to make unnoticed purchases of weaponry and unbalance the carefully-constructed detente that many rival houses exist in - or they could use it to essentially commit tax fraud, to mask how greatly their Holdings are prospering. I am highly doubtful that the Empire would allow capsuleers to pull any more foundation-stones from the social dynamic of the Empire than they already have.