1. So? The U.S. is and has been full of socialist systems for a long time. Any central planning, any government welfare is socialism. The question isn't whether to engage in socialist practices, the question is where you set the sliders. We're already a socialist nation, we just like to pretend we aren't.
2. Because the rich derive more benefit from the economy than the poor. This is self evident. People who own businesses, or make their money off of businesses, benefit disproportionately from government spending, particularly infrastructure spending. It takes roads and internets and telephones to do business. It takes courts to enforce contract law. Who uses courts more, individuals or corporations?
3. Not borne out by any sort of evidence. The best predictor of wealth is to start wealthy. After that, it's education, which costs money. Working hard may get you ahead, and may leave you living on the street.
4. Except for a few limited areas, the U.S. doesn't have the best healthcare. A lot of this depends on how one defines best. It's pretty much dead last in coverage versus cost per person, and not that great in a host of different areas. Not only aren't we the best, but many countries with better overall outcomes pay a fraction of what we pay.
5. State university costs have exploded dramatically, along with private universities. Nearly all are considerably more expensive than their counterparts elsewhere.
6. You should slap them in the fucking mouth. Slavery and theft have meanings, and taxation fits neither. They are welcome to pick their asses up and find themselves a country with kinder tax laws whenever they feel like it. Of course, to do that they'll likely have to live in a place with little government (which answers the next question), no protection from the predators that would like to take their money, no courts to protect their assets, and no infrastructure to speak of.