Nonsense, that blog is one massive masturbatory hyperbole ridden scaremongering sack of rubbish - and then people like you come along and condense it into a sentence and misrepresent it even further.
So they store their passwords and they're just encrypted, big deal. It's a password for a supermarket it's not that important. If you're using the same password for anything else then it's not Tesco that are the weakest link, and if they do send you out a password reminder of your unencrypted password and by some chance someone can get access.. I can't see a way to easily monetise that given to spend any money with them you'd need the 3 digit security number, verified by visa or mastercard securecode.
There's far too much financial/password scaremongering goes on and irresponsible Hunts like Troy invariably have a vested interest in security hysteria.