I am not contesting the Jewish Encyclopedia but the NT. When the Jewish Encyclopedia mentions "according to tradition," it means according to the NT or Christian tradition. It is not stating anything as an endorsement to what the NT or Christian tradition stand for.
Here, the reference in the Jewish Encyclopedia is to a later group of former Nazarenes, whose synagogues Paul had overturned into Christian churches throughout Asia Minor and later in Israel. Evidence of the fact, we have in the Nazarene synagogues of Antioch, Galatia, Ephesus, and all the others. Paul was, obviously, unable to raise a church of Gentiles from scratch. He would act like the Cuckoo bird laying its eggs in foreign nests. But the original Sect of the Nazarenes had nothing to do with Christianity till Paul entered the stage.