What I don't get is that this is useful regardless of bikes. If you're opening your door on the street side, then a vehicle could also rip out your door/you. The "Dutch reach" prevents that just as much as it prevents killing a cyclist. I dunno I do live in the Netherlands so maybe my perception is warped, but I'd never just swing my door open street-side without checking, bikes or no bikes.
I don't know how or why this is always attributed to the Dutch. I'm Dutch. We definitely did not learn this. Not in school, not from parents, not in driver's ed. We do not open our doors this way.
The thing is that all Dutch drivers are also cyclists, that helps a lot. Also, our infrastructure is very very very VERY accommodating to cyclists. Often bicycle paths are separated from roads,which helps a lot.
When opening doors, we simply look. There's a mirror very conveniently placed for the sole purpose of looking behind you. Use it. If you open your doors without looking and thinking, you're an idiot. None of that has to do with being Dutch.
Dutch kids learn it from parents & in school.
It’s taught in drivers’ ed, and used to pass their driving test.
It's been Dutch commonsense for 50 years.