Regarding BlockChain.info u have stated this...
The developers of this wallet publish the source code. This means any developer in the world can audit the code. However, you still need to trust developers of this wallet when installing or updating the final software because it was not built deterministically like Bitcoin Core.
But, AFAIK, the complete source code is not open like Bitcoin-QT. Only the client side JS is open. Please check the bottom of
https://blockchain.info/wallet/securityWe dont know what is happening at the server side !!!
To my understanding, transactions are signed locally by the app, so blockchain.info servers can only be used to get data from the block chain. The "decentralization" score takes care of this part: "This wallet relies on a centralized service by default. This means a third party must be trusted to not hide or simulate payments."
This being said, if someone can prove me wrong and show that any of these centralized servers can do more than just providing block chain data when the open-source client is loaded, I would certainly agree to use the "closed-source" dialog instead.