I don't trust that data (haha, trust). how do they ascertain trust? By asking? It might be true that Scandinavians claim they trust their neighbors but those are places where your stuff will get stolen, packages get stolen, you don't leave stuff on a public table to use the restroom if you don't want it stolen. In other words, you can't actually trust people. They list Japan as less trusting, even less trusting than that USA. But, actions speak louder than words. You can trust others in Japan. You can't trust others in LA, NYC, SF Bay Area, Seattle, Chicago, and other major metropolitan areas of the USA (the places where everyone lives.)
So, it seems like their methodology doesn't actually match reality and is why I don't trust their results.
Trust is not just petty crime. It's everything from crime to business transactions and more.
I might leave my laptop on a table while I use a public restroom in China, but I sure as hell trust a business partner far less than I would one in the US on average.
Cultures differ greatly in how trust is assigned and expectations. There are areas in Eastern Europe I would walk through a dark alley at 3am in the 'bad' part of town and not think twice about it. But I sure wouldn't trust their police force to not be corrupt and expect a bribe if they hassled me. The reverse holding true in a major city in the US.
So, it seems like their methodology doesn't actually match reality and is why I don't trust their results.