this has nothing to do with kessler syndrome. If anything, it's the opposite: satellites that are low in orbit deorbiting naturally. The article fails to explain why deorbiting sattelites at this frequency is bad, it just loosely suggests it with nothing to back up the claim.

The earth's atmosphere is pretty big, and sattelites are just made out of aluminum and crap. I don't think it is a big deal.

I could search this topic on google scholar for hours, but I can already tell the result is that I would probably find nothing of substance.