A person opening a door does not have a usable perspective to do that. The cyclist does. When I rode, I assumed any car was an enemy, especially the ones that came to a stop. It is so very common that someone is bound to open a door to get out; for, that is what the stop is all about.
Of course he does. There’s a side mirror; and most people who can drive are physically able to twist around and look to see what’s coming down the road.