As far as "objectively safer" - not sure how that works (or matters). Since when has safety actually mattered in terms of public opinion? If safety mattered we wouldn't have cars on city streets at all, all last mile would be slow & public and we'd have built our towns & cities to support that.
And broadly speaking, with more varied training data you can achieve better out of sample results.
In Vietnam the effective priority of vehicles is "biggest first". A neural net trained in that environment won't be very useful in the UK, where priority is defined by road markings and street signs.
However, as someone who regularly visits and drives in a 3rd world country, there's a "vibe" to it if you will, and once you learn the vibe it becomes natural. (It seems to be that people respect the laws of physics over the laws of the land, if you will) If you train the cars on a 3rd world country's driving patterns, further refinement will be necessary to fit in better in a more developed country. But early on it will deal with stuff like driving on a road with no lines at the edges or between lanes, one lane bridges, sharing the road with pedestrians, cyclists, motorcyclists, and animals, etc.
You're correct when you say
>we have numerous companies testing autonomous vehicles in the states
The article we are responding is is about increasing political pressure against that practice.
I've had the thought that third world countries will end up being the testing ground for autonomous vehicles. Peoples' safety isn't taken as seriously in developing countries, and the local authorities are easier to bribe.
The cost for actually functioning autonomous vehicles will be some mistakes. It's up to society to decide whether the ultimate value is worth those accidents. The modern world has a history of offloading certain types of hazards (such as hazardous waste, dangerous factory conditions, etc) to the third world and I see this as another use case for that pattern.