Simply put, in today's language, the religious leaders set the narrative and they silenced or eliminated anyone who went against it. Saul is a perfect example. Saul was on his way to Damascus to arrest Christians who would probably, eventually, be killed.
Force the belief that Jesus wasn't the Messiah and the people will know no different after a time.
It was indoctrination.
Again, JMO, YMMV
Saul's conversion is a good example of how difficult it was and is for Jews to accept Jesus as Lord and Savior.