Ah, see that's where not reading is a problem. Just saw star link competitor and remembered something a recently about China looking to launch a similar system.
Odd they would phrase it as a 'starlink competitor' then though rather than 'a new ISP bid'. Wireless systems with directional antenna relays are not really new, not sure if any use laser particularly but the concept is essentially the same.
At sufficiently low orbits, the satellites would simply deorbit themselves because of the atmospheric drag. Several Starlink sats have been lost this way.
Yeah, more thinking the wasted time, resources, and emissions involved in building, launching, managing, and then whenever makes it down.
Take all that and make something useful instead, whatever happened to Google fiber being built out all over? More reliable, faster, doesn't involve sending piles of redundant satellites into space...
Supposedly traditional ISP's have tons and tons of lawyers and filed every single step of the way to stop Google from intruding on their local monopolies.
When they say "burn up on reentry" they don't mean disintegrate, they mean burn. It's exactly like throwing thousands of home entertainment systems in a fire except that the pollution is in the upper atmosphere where normal pollution doesn't reach.
I don't know about the ozone layer specifically, but reentry turns the satellite into danger dust -- mostly metal oxides and burnt polymers. Ozone, being a very strong oxidizer, is the most likely to react with the hot debris, so it probably does damage the ozone layer, but I can't quantify the damage, or the released pollutants.