They’re probably using green to mean “not CO2 producing” given the context of the discussion being about CO2 emissions

I understand the argument and yes CO2 emissions are indeed lower. However, only marketing/sales/lobbyists/politicians would use that to sell it as green energy. It's not green, it's not environment friendly, it's not renewable.

Actually one could argue that it is extremely environment friendly, seeing as Chernobyl has become a wildlife sanctuary.