SpaceX wants their Starlink constellation to crack 100,000, and there are plenty of competitors lining up who will surely want to have "the biggest and the best" at some point. None of those sats stay up terribly long, so you'll have a constant cadence of launches and reentries, both of which are a risk for their impact on the climate system, atmosphere, etc.
A largely unstudied risk, and once which will almost certainly be strenuously ignored for as long as possible.
Those are rocks, which are not made from the same stuff as satellites. (Also, the article says it's 44 tons, and other sources suggest around 50 at most.) In any case, I don't think anyone here is "freaking out", I just think this issue merits investigation.
Why do you consider the ideal point for this question absolute 0 zero reentries rather than the minimal number of reentries that don’t cause damage to the atmosphere?
A largely unstudied risk, and once which will almost certainly be strenuously ignored for as long as possible.