I will preface this with 'it is my opinion' and that I'm simply a high school teacher who works with the kids who are supposedly part of the computer age (emphasizing supposedly... since the vast majority don't know what a server is, what a cpu is, the difference between ram... but I won't go on a rant about that here...).
There are certain companies that are clearly leaders in the computer/internet/etc field. Apple, mirosoft, IBM, CISCO...etc). This is simply a case of one of the bigboys updating their software (on behalf of users everywhere) and the smallboys understanding what these updates entail as far as the workability of their programs. (I can give a long lecture here on the 'New' VS the 'Old' Imigrants in US history (or any country's history for that mater)). A lot of times the smallboys are arrogant enough to ignore the warnings, the newspaper articles, the emails, the test versions... of these new updates. (It may (however) been a lack of cooperation putting the blame on Apple (but I think if even amateur like myself paid attention to the updates before they came out officially). But I really doubt that based on Apples history.)
There are very specific malware, anvirous, and computer basic protection companies that failed to look into Apple's update before the update what put out to the general public. Apple advised us to, when the companies we use (and I use top of the line protection services (not the free crap)) worked their softwar to be compatible with the bigboys (Apple) update it was simply a matter of un-installing all our protection systems and re-installing them (granted... not an easy task... but ... the point is... if they had tested their software when apple offered test versions... (assuming from my amateur eyes they did) then they could have updated their software before Apple institued a software update to the general publik(with a russian communist version of the word for those that disagree with me))))))))). (A few extra parenthesis since I over use them (sorry (very sorry)).