It could be as simple as wanting to experience another culture. I spent a semester studying in China. I didn't do it because the school was better (although it happened to be), but because I wanted to spend time in China.
Why would you say our society is worse? Every country has its social and political and economic problems. True most western countries and a few asian countries offer a simewhat better education but the US has a much better education system than many other countries. Different does not equal better or worse. Just pay attention to the news and you can see the social and political unrest other countries deal with. Every western country deals with immigration issues, prejudice, crooked politicians, economic problems, etc.
We have the best universities in the world. K-12 is a different story, depending on the social aspect and economic standing of the districts. One high school has kids building robots, while another has kids watch a recording of myth busters. One school brings kids to the Intel museum, another has them read the bible.
Many foreign exchange students experience a slice of our culture, representative or not, by spending a year of high school equivalency living in a household that is generally above the economic status of the community. University attendance & training in America attracts students usually looking for citizen status & higher income than their own culture would give them for whatever work title they pursue. Of course, America allows for free speech that isn't permitted in certain other countries, too. However, in general, our K-12 has been sub par for decades compared to anything but what we call Third World Countries. & higher education is rapidly becoming unaffordable for nearly all American citizens.