Anyone who thinks a short password is secure in this day and age is nuts - particularly as just such individuals re-use passwords across services.
This person would be the first to decry SO if there was any breach of security caused by bad password choice.
Should you have persevered through the terribly difficult task of establishing a password with them then - wow- you would have had a new OpenID you could have used at other sites - without creating yet another username/password combination.
These guys are doing you a favour at their (small) expense and you see it as some sort of con.
Some word combination of horse teeth and gift comes to mind - but whingers there will always be.
It really does smell like link-bait by singling out two large sites.