You are right that this happens frequently in the United States compared to Europe, but you are overstating the degree to which this culturally and legally acceptable. People who are doing this are not typically broadcasting it to others, and I can assure you that when they do, for the most part people will tend to "bat an eye" at the very least.

Note that motor vehicle insurance in most of Europe is more tightly regulated and generally more affordable than in the United States. Also, I suspect the car-dependent individuals in urban areas with robust public transportation in Belgium are generally vastly higher income than the typical uninsured compulsory driver in the United States. Happy to be corrected though