Try this. Go to your local back and make a withdrawal of YOUR MONEY... After all it is your money, and see what happens if they tell you Oh we are sorry but withdrawals are delayed and you will get YOUR MONEY in 6 weeks... Yea right..
It's called a bank run. Happens quite often.
Maybe if you live in Greece or some third world hell hole. In the US, depositor`s accounts are insured up to $250,000.
On the BTC exchanges, your accounts are not insured at all, and you actually run the legitimate risk of having your funds mishandled or downright stolen. So OP has a point.