If it was a non-complicated, easy to figure out password, then yes, it is their fault.
I think you might have forgotten how the hackers actually got the accounts?
They didn't guess any passwords, actually they didn't even get to know the passwords.
No, they found a way to download the exact file with both your POL ID and your password by executing a simple script spread over a huge amount of websites and occasionally even put into new hardware like a new external hard drive or MP3 player you bought in a store.
Is it the player's fault for allowing mailicious scripts to run on their computers?
Perhaps, but when even antivirus software and spysweepers aren't up to speed yet there's not much you can do against something you can't see until it is already too late.
Is it a consumer's fault that they are buying something that has been bugged by a kid in a factory?
Before going 'oh but you shouldn't visit somepage'.
thousands of sites hit with scripts specifically written to get your FFXI/WoW/RO/whatever MMO accounts.
And a few of those aren't small mailicious or game specific sites either.
creative.com and even my own company's site c1000.nl (grocery store site) were hit by hackers leaving this 'gift'.
And please don't go, 'you should've used firefox' because many people that lost their accounts are or were firefox users just visiting a site they normally trust(ed).
The exact same could have happened to you.