I think he's assuming that since the CIA is now a big customer, Amazon will bend the rules and give the CIA access to data from other customers, or at the very least the CIA will now have better experience in how AWS works so they'll be able to attack AWS customers more effectively themselves.
If they wanted to experience how it works, wouldn't they just be able to sign up under an alias? Also, I am not American, so I might be out of the loop a little, but why does everyone consider CIA to be some big bad wolf like in the films? There are probably people risking their lives (maybe not in an action movie way) right now, trying to make the world a safer place from terrorist ducks.
Because the CIA has a long history of directly and indirectly supporting assassinations, drug trafficking, propping up dictators and other unsavoury actions that puts the CIA very high on the list of organisations that have carried out the most terror activities worldwide.
Sure, they also do good / important work. And it's hard to say if they're still as bad as they used to be, as it'll take decades before the most important details about what they're doing now gets declassified. But their history doesn't exactly give a lot of confidence.
