Hadrian was a pedophile (after his catamite Antinoos died in the Nile, he had a city built at the site named after him, had him 'deified', and set up places of worship all over the Roman Empire), and despised the Jews in part because he considered circumcision to be self-mutilation. Throughout his reign he showed that he backed pagan Hellenism and supported the destruction of Judaism.
Need to go back to reference where I read that Hadrian was easier on the Jews and wanted to rebuild Jerusalem.