This chart may not be accurate.
If American Hindus are really communitarian, then why do a large majority of American Hindus support same-sex marriage and abortion?
Well, being communitarian doesn't necessarily entail being socially conservative. There's a correlation, but that's because Abrahamic religious morals are more prevelant in the West (obvious fact is obvious).
With homosexuality and non-Abrahamic religions, a possible attempt at rationalization is "Hey, we can give the gay couple the orphaned kids since their parents died. Nothing in the scriptures says anything wrong with homosexuality, and we asked them and they said they couldn't change, so who cares if it doesn't hurt anyone? Maybe they were the opposite gender in the previous life, so they're not used to it. Guess it's all part of the karmic plan or something! *shrugs*".
And with abortion, the shame of pregnancy out of wedlock could bigger than abortion. Or they can't support another child.
This. By and large Eastern culture considers the shame of out of wedlock pregnancy far worse than the act of abortion hence the fairly high rates of abortion in East Asian countries.