This does not follow. Photons from the sun are not radioactive isotopes that can rain down on us as they decay from orbit. And the magnetosphere protects us from the bulk of the solar wind's traces of heavier isotopes. How much plutonium or whatever, is in near-Earth space, other than what we've sent up there? The old Soviet reactor-powered RORSAT series have their cores in orbit still. They'll come down eventually. See
https://en.wikipedia.org/wiki/Kosmos_954 which crashed in the Canadian arctic. A cleanup operation was attempted over a wide area, as it survived reentry with pieces intact.
> They were ultimately able to recover twelve large pieces of the satellite, ten of which were radioactive.[1] These pieces displayed radioactivity of up to 1.1 sieverts per hour, yet they only comprised an estimated 1% of the fuel. One fragment had a radiation level of 500 R/h, which "is sufficient to kill a person ... remaining in contact with the piece for a few hours."
A more pragmatic argument is that, after the fission of literal tonnes of plutonium in the atmosphere in the previous century, the small risk of losing a few kg more here or there pales in comparison. Even all those RORSATs barely register in comparison to that.
