Why some people and governments suppress Baha'is people?

The reason for the suppression is that Muslims believe that Muhammad was the "seal of the prophets" and that no one could come after him. However, Bahais believe that Bahaullah came after Muhammad and therefore they are branded as heretics by many Muslims. Therefore they are persecuted in several (but not all) majority Muslim countries. There is a similar situation with the Ahmadiyya movement.