Is shoveling so much trash over non-american land actually legal?
Not that these launches are launching trash, or launching very much in the grand scheme of things either.
Either way, a few thousand things spread out over the surface area of the earth is practically nothing.
and the surface of a sphere at the altitude they're orbiting at is even larger. and the satellites are all spread across a variety of altitudes, relative to their size.
it's up in geosynchronous where things are carefully planned, and the spacecraft can adjust their orbits, and do lots of long term station-keeping.
Second, I imagine outer space treaty covers this in much similar way that treaties governing international waters do.
Third, to a certain degree "satellite trash" is in the eye of beholder - I don't think there's any more or less legality in this, than in ISS, TV and comms satellites, GPS, etc all flying all around the world.