Telling people not to worry about security works until they, inevitably, have their data compromised. Technically aware consumers have a responsibility to put pressure on companies to be secure with information.
Millions of accounts from a single breach somewhere. Not millions of accounts individually brute forced because their case-insensitive passwords made them trivially guessable.
We should be worried that Blizzard will get hacked like PSN was. That would be potentially catastrophic. But case sensitivity has almost no effect on password security unless your users ALL use random passwords.
"Technically aware consumers have a responsibility to put pressure on companies to be secure with information."
No one's shown that Blizzard has been unsecure with anyone's information. I see a lot of people running around like the sky is falling when it's not.