This is a very poor argument. Not only can two billion people easily be wrong. It does not work if you go by your poor standards. Roughly one third of the world's population is Christian. That means that 4 billion people do not believe that he rose from the dead.So 2 billion people that believe Jesus physically rose from the grave are wrong? Wow! That’s a lot of gullible people! Haha.
Using an ad populum fallacy when one is in the minority is just shooting oneself in the food. one loses either way.