Was the famous DAO attack on Ethereum actually a 'crime' in the normal sense?

Hear me out...

Having read 'Out of the Ether' by Matthew Leising (great book btw for anyone looking to learn about the origins of Ethereum) I found myself considering the DAO attack and whether there was a theft and a crime committed?

I guess this is more of a philosophical question as yes obviously everyone who sent Eth to the DAO was essentially entrusting their money and I don't condone someone taking millions of dollars from average people; however entrusting it to a smart contract which anyone could view the source code to is different to say entrusting it to an ordinary bank.

If everyone could view the source code and hence it's vulnerabilities then surely the responsibility is on the sender to know what they're sending their money to (granted you'd have to be a computer genius but still) then no crime has been committed because the laws of the contract are there in black and white.

It's a bit like sending your money to a bank whom you trust, but in their small print terms and conditions it says actually anyone might take your money for their own purposes and theres nothing we can do about it. Obviously no one would use a bank like that, and if your money was stolen you wouldn't say a crime has been committed as the bank stated that it might happen.

I'm interested to hear people's thoughts as well as the legalities of what actually went down!

Thanks!