Reality check
Firstly, people flipping out assuming anyone in Apple PR green lighted this, just hasn't been paying attention. Apple doesn't roll that way... The employee who released this (if identified), is probably an ex-employee by now, or soon will be (HR works on weekends if needed).
Note: With all of Apple's media distribution networks to call on, a post on twitter, with content hosted by twitter just isn't likely (post appears to have been from @beatsbydre via twimg.com).
Secondly, having been part of a relatively recent 'Merger via Acquisition'... It's not uncommon for one side of the newly merged entity to release something that doesn't tell the appropriate story about the overall brand (There' some crazy embarrasing stuff still up on one of our youtube channels).
Judging by the timing, and how long it would take to have someone craft a commercial (even of low quality), this was already ready to roll. No one in Apple PR would have let this out to the public, though it might have been used internally, but even that's not likely... You don't poke fun at the new team (regardless of which side of the fence their on). Hence the release timing (EOD on a Friday)... It takes a much longer time for someone with the appropriate access and authority to remove something posted after hours.
As far as how it got out... Corporate twitter accounts are supposed to be accessible by a select few. Unfortunately this is rarely the case, and people with access who shouldn't have it just don't post for fear of repercussions... but when you have just been told your job is now 'temporary' and you know the team from the smaller company is getting boxed as soon as the merger paperwork allows... there's nothing to stop people from posting things that never would have seen the light of day otherwise (especially if you were smart enough to post by proxy and they can't pin it on you).
I bet the keys to all public facing accounts are under Apple PR's control by EOD Monday.