The article contains an observation that the Facebook app reads accelerometer data. It contains no evidence that Facebook retains this data, stores or uploads it to Facebook servers, or uses it for any purpose other than what is stated (some kind of camera thing and gesture recognition for bug reporting).
The rest is made-up speculation about what they “wonder” Facebook could do with this data if they were storing it - which, again, they have no evidence to suggest is happening. I find the idea that you can effectively use accelerometer traces to correlate the location of devices to be extremely unlikely in practice, even if theoretically possible.
Meanwhile, this site itself is so festooned with trashy ads and pop ups such that only about 15% of my screen is available to display the actual article text.