Earlier quoted context omitted.
He favors European style social democracy. His whole point is that there actually exist functioning countries where health care is universal and free, college is accessible to all, gay people have rights, etc etc., and that America could be one of those countries if we wanted to. Btw I learned this by spending five minutes last night reading about him and watching a short interview, so I think your comment gives him…
The problem with the U.S. and why universal health care potentially wouldn't work is in terms of scale. The U.S. has over 300M people living in it, over 8x as much as the most populous European country. We also have a history of hating and evading taxes at all costs (Boston Tea Party). I'm not saying it can't work but the economics gets truly tricky when you're dealing with a country that big.
So, set some very basic standards at the federal level and make the details and implementation a state responsibility. The largest US state is significantly smaller than the largest European country that provides universal healthcare, so that should solve that problem more than completely.