But in a nutshell his point is that by its very nature GPS data collected over a constant time period cannot be anonymized. If your car is located >50% of the time in one of two places, chances are one is your home and one is your office. I now know where you live (and thus your identity) and I know where you work.
Everyone here is assuming anonymize means to remove name but keep everything else intact. I see no indication that this is the case. If there is reason to believe otherwise, point me in that direction.