Hello, I never claimed to be an expert. I'm pretty sure I know how the stock market works, but you would have been correct had you suggested that I don't know how corporate officers liquidate their holdings.
A year is enough time for them to get the feeling if and when the music might stop or go against them. Tax loopholes (especially Ireland related) have been in the news for a while. They also did a 7/1 reverse split this year, probably trying to get the numbers up a little before cashing out.
If you read between the lines you will notice that most of the people referenced in that article liquidated all or close to all of their holdings in Apple. Regardless if they planned it a year ago or not I think it was pretty convenient they liquidated right after the iPhone 6 release.