Why did people hate the ancient samaritans?

Generally, the ancient samaritans were hated by the Jews and the Greeks. To the Jews, Greeks were "Gentiles", meaning that they were not Jews. Therefore, they were polytheistic (they believed in more than one god) and unclean. To marry a Gentile would be a heinous crime in the Jewish community. Samaritans were generally Jews and Greeks that were intermarried. Once this was found out, both individuals (the Jew and the Greek) would be cast out of their own communities, forcing Samaritans to build their own towns and cities. To sum it up, a Jew would be hated for marrying a Gentile for the above-listed reasons, and Greeks would also be hated for marrying out of their polytheistic religion.