It always seems like a good idea in security to emphasize prudence over accuracy, possible risk over evidence of actual attack. And frankly this policy has been run by the privacy community for some time now. Is this a positive shift? It certainly allows an answer to the question for your average consumer, “What am I supposed to do in response to this Internet ending bug?” “Well, presume all your passwords leaked and change them!”
I worry, and not merely because “You can’t be too careful” has not at all been an entirely pleasant policy in the real world. We have lots of bugs in software. Shall we presume every browser flaw not only needs to be patched, but has already been exploited globally worldwide, and you should wipe your machine any time one is discovered? This OpenSSL flaw is pernicious, sure. We’ve had big flaws before, ones that didn’t just provide read access to remote memory either. Why the freak out here?
Because we expected better, here, of all places.
I recall the days of hearing from people that open source software was dangerous because anyone could add any code. The usual counter was that because it was open, someone would see something that was inserted that was malicious. While it doesn't look like the Heartbleed bug was introduced purposefully, the problem code wasn't found soon enough.