I think it might be because the US required goods to have "Made in wherever" on items for longer than most countries. I recall a reference to this in Dana Thomas's book "DeLuxe" where she recounted scenes of workers removing "Made in China" labels, as they were not required in most places. Most EU countries do not require any info on country of origin. There was this WSJ article about this topic:
http://online.wsj.com/news/articles/SB10001424052748704062604576105691622922576
First 3 paras:
BRUSSELS—A proposal that would force companies to slap "Made in" labels on billions of euros in goods sold in the European Union has split the bloc's southern manufacturing base from big, mostly northern, multinational companies that sell items imported from abroad.
Trade experts say the idea's popularity in the EU—it has been approved by the EU Parliament and the European Commission—reflects concerns over a struggling economy and losing jobs to foreign competition.
It is odd that the heavily regulated EU doesn't already have country-of-origin labeling. Similar tags are mandated around the world, including in Japan and China, as a way to help domestic producers compete against foreign manufacturers. The U.S. has had origin labeling since the 1930s. Roughly a quarter of consumers make choices based on where a product was made, according to EU surveys.