The real answer is:
In the US, standards for towing loads are established by the DOT and it's subordinate agencies, while overseas there are a myriad of such standards that vary depending on where the vehicle is sold (even in the EU countries there are variations of standards for how vehicle towed loads are rated)
In some countries around the globe, there are no set standards, so the car auto OEM sets the payload limit (and of course that can vary from country to country for the same model auto).
You are comparing apples to oranges.
And the DOT has to set those standards in regards to higher speeds with higher loads over longer distances for less rigorous driving license granting standards. So basically what I already said you just added a rather obvious addition that "an authoritative agency frequently sets standards in countries" and are trying to elbow in on my rant about American vehicle culture. The nerve!
Look the US now has this culture where a large percentage of the drivers "must" have a huge vehicle for no great reason beyond they want one but can't admit that's the real reason. "Oh I have two kids now in car seats so I HAVE to get one." Totally doable in a sedan. "Oh I want to go camping so I MUST get a large vehicle" Yep also doable in a sedan. "Twice a year I go to Home Depot and buy plywood". I mean ok. Just rent a truck for those rare occasions.
But we also complain about the cost of trucks and SUVs. And gas. But we still buy them for incredibly infrequent, solvable, or made up problems.
Now there are 100% reasonable situations that need a large SUV or pickup. But so very many are really just status symbols and garage (or growingly common driveway) queens. If you want one for the sake of wanting one AND can afford it AND moderate your complaints about price and gas? Fine. Just be honest about it. I mean in a couple years I'll probably buy a way more expensive car than I need. Why? Because I want to and can afford it