Actually, to the Jewish and Roman authorities, he was. 1) he performed "miracles," which in his day were considered to be magia (magic, sorcery) and even then that sort of thing, whether done for good or ill, was considered to be antisocial and threatening. 2) he performed miracles on the Sabbath when people weren't supposed to perform Works 3) he was preaching heretical and mystical ideology, which the Jewish authorities, didn't dig, 4) he is depicted as being a leader of a religious cult if not a political cult. Romans didn't like religious cult leaders; they strongly felt that if their gods weren't respected in the appropriate way, calamity would come to the Roman nation, so they had zero tolerance for cults and religious leaders that they thought were antisocial or threats to the status quo. Of note, however, is that the Romans kept meticulous notes about people they thought were threats and what was done with them--much like our own govt in keeping track of "terrorists" etc. Nothing is in the Roman record that corresponds to the Biblical story about Jesus, although plenty of would-be messiahs were executed as political anarchists and threats. This info does not come from modern pedestrian interpretations of the Bible, but from historians of the Biblical era (the turn of the first millennium of the common era).