UAC flaw "by design" says Microsoft

Microsoft dismisses Windows 7 UAC security flaw, continues to insist it is “by design”:

Just because it’s by design doesn’t mean to say it’s right. This is exactly the blinkered thinking that we heard from the people working on UAC in the Vista timeframe — “This is the way it’s going to be, we know better than you.”

Since that attitude was provably incorrect last time, what makes it any more right this time?

(Via I Started Something.)