Even today, being born a country does not mean automatic citizenship. See Japan, for instance.
Additionally, the Jews still considered them interlopers during Jesus time. Furthermore, the Samaritans had continued to be fifth columns allying themselves with foreing powers.
The Jewish Supreme Court had not decided that native-born foreigner was the same as a Jew. The Jews couldn't wait until they had their kingdom back to take over Samaritans' lands.
Therefore, Jewish people need not consider them their neighbors.