It’s embarrassing the author is even suggesting it’s relevant.
Also, I only connect to Facebook via Chrome, on my desktop Mac at home, where I use Firefox for all other browsing; on my phone and laptops, I don't use Messenger or connect to Facebook at all. I'm sure they have found sneaky ways of figuring out more about me than I'd prefer, but not so much that additional security precautions seem worthwhile.
100% = 100-9=91
53/91=58% did not change anything
24/91=26% tightened settings
14/91=15% deleted account
+/- 1% due to rounding
47% seems huge though, even if the sample was biased from a technically savy population.
The only way to tell will be the trend, not the snapshot.