Why did Romans come to consider Judaism a threat?

Only one Roman Emperor, Hadrian, considered Judaism a threat. He sparked a rebellion because in his plan to rebuild the destroyed city of Jerusalem he decided a temple of the Romans goddess Venus and one dedicated to Jupiter Capitolinus, the chief Roman deity. The latter was built by the cite of the destroyed Jewish Temple. Hadrian also forbad circumcision, which the Romans considered barbaric. The Jews saw this as an outrage and oppressive. This sparked the Bar Kokhba revolt which lested for four years (132-136). This sparked a massive rebellion, the Bar-Kokhba Revolt which lasted four years (132-135 BC). Hadrian had to call troops from elsewhere in the empire. The rebellion was put down, but the Romans suffered heavy losses. According to Cassius Dio 580,000 Jews were killed and 58 towns and 985 villages were said to have been destroyed. After this Hadrian tried to stamp out Judaism, which is saw as a cause of sedition. He banned the Torah and the Hebrew calendar, had the sacred scroll burnt and executed Jewish scholars. The Jews were not allowed into the Jerusalem, which decided to rebuild as a Roman city and he renamed Aelia Capitolina (after the name of his clan and that of the god Jupiter Optimus Capitolinus). He also abolished the name Judea and replaced it with Syria Palaestina (after the Philistines). Later the Romans adopted a policy of respecting Judaism.