I'd expect bicycle riders to be aware; and, it is their responsibility to protect themselves with equal measure.
Why do they teach drivers to slow down really slow and toot the horn when passing by a stopped delivery truck? This is exactly the same situation, different types of vehicles.
It could just as easily have been another car. I think the person opening their door has a responsibility to see if anything is coming.
Helmet rules tend to be more lax overseas. Wonder if that factored in at all. Very sad.