Firstly because it's just an interface, there is no storage or website...
Secondly because if you've been hack, it's not because of myetherwallet, but always a human issue.
If your password has been hacked it's not because of myetherwallet, they don't store it. It's because of your pasword's weakness.
When you store thousands of euros, it might be usefull to find a strong password, not a 8 digit password... Except if you don't care loosing your money...
The other way to be hacked, is cliking on a false link. Some people send you to false myetherwallet link like my-etherwallet.com or other stuff.
Don't clik on it... Or it will send your password when you type it, to the hacker...
Good luck and sorry for your loss
Well said. I think users need to be aware that MEW can be brilliant in its simplicity, but only when used in a safe way - which is the obligation of the user, not MEW.