You do something enough times that it just becomes automatic, like when you get E-mails from Blizzard you click the link and go to their webpage,oops look it isn't their webpage, but the nuances are so small that you didn't notice. You've gone to the Battlenet.net login screen a thousand times but oops you didn't notice that you just went to battlenet.net instead of battle.net, yet it looks the same so you login in as you usually do.
You've been phished
You assume people are not aware of phishing. I NEVER click a link in an email that I was not expecting to get. If you get an email from blizzard, your bank, paypal, whatever, saying that you need to do something with your account. You open your browser window,s and you type in the address yourself and log in. Anyone who is aware of phishing knows that you should be using this route.
Only time you should be clicking links in emails is when you have to in order to authenticate a new account you have made, in which case you should be expecting the email to come from a certain site at a certain time. Unless the site you are signing up for is not legit, you should not have an issue.
If you do sign up for sites you are not sure of, this is why you have a secondary "junk" email account. So your main email is never exposed.
I find no fault with your statement, except, I find it hard to believe that you don't have your favorite links up on your browser bar and actually type in your web adresses everytime :-) (no it doesn't have anything to do with clicking a phishing link, I just couldn't find fault in your statement :-) ) Oh Wait, that comma doesn't need to be there in that word!!!
But like I said, we become complacent. It IS our fault if we click a link in an E-mail. I've done it when a friend sent me a ressurection scroll so she could get a new digital mount in WoW, even though I made her pay for the month cause I am so tired of WoW.
Later I received an E-mail from Blizzarsd(not a typo but it was hidden unless scrolled over and I didn't think to do that at thet time) inviting me to MoP Beta.
Having a close friend who was actually in the MoP Beta, I clicked the WoW link and found myself on a page that had Blizzards MoP details, but with some slightly noticable errors.
I E-mailed Blizzard and asked about it, they told me it was a scam. I scrapped the E-mail and link.
User Error. If I got hacked (though I have an Auth that saves my butt) I wouldn't go bishing about Blizz, i'd jsut ask for a roll back and learn from it.