The intention of the post was not to whine about the password complexity. Quite the opposite, I think Stack Overflow's strategy is a brilliant way to get you to login/register using Facebook.
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.