Because along with the USA's population being larger, it's also far more diverse. New England is roughly the same size as a typical European country, with a higher HDI, similar GDP, and similar crime rate. In France, the population is not nearly as diverse and so the crime rate, HDI, etc. is roughly the same in every part of the country. The laws, economic standards, and regulations are also the same across the board, which is not how it works in the US.
Anyway, the 'meme' I posted was not to be taken seriously - just bait, like most of the shit in this thread. The data in my image does seemed to be backed up by numerous sources, but I don't know with what criteria they came to that conclusion, nor do I really care enough to find out. The quip about weapon laws in France was also unrelated.