Are you really comparing bridges to be replaced every 50 years, and regular satellites expected to operate for 2 decades, with these Spacex sattelites which are expected to last 5 years?
Residential broadband involves millions of items such as switches, transceivers and billions of miles of cables. Much of this is replaced every 5 years by ISPs. Not even taking wireless routers into account which are probably replaced much sooner than that.
I'd imagine Starlink at least has less impact than our current infrastructure.
So you're saying we shouldn't put networking equipment of the sort in LEO? I don't understand your position. Switches in datacenters and deployed to provide internet to consumers are thrown away very frequently, and LEO satellites don't pollute their orbits with debris since unpowered flight at these altitudes regresses due to atmospheric drag (that's a desirable outcome). The timing works out.
I prefer this to an alternative where a failed constellation would be left as garbage to orbit the planet for decades/centuries. And I'd bet a few thousand satellites in space (including fuel used to put it up there) has an overall lower impact in the environment than the sprawling equipment and cabling needed to do the same coverage if using ground technologies (including all the resources used to install and maintain said equipment, and ecological damage).
I'd imagine Starlink at least has less impact than our current infrastructure.