“Majority” is one of a few nouns in English that can be used either with a singular or a plural verb. These nouns are called collective nouns because they describe a collective (i.e. a group) of people or things. Their usage in English differs from most other languages: We use a singular verb if the whole group is understood as a single entity, and a plural verb if we are referring to all individuals who belong to the group. For example:
Here we are obliged to use “don’t” because we mean the people, not the “majority” itself. On the other hand, we would say
because here we are referring to the “majority” itself, not to the individuals. The list of collective nouns includes, but is not limited to:
For example, you can say “his family are all tall”, when you mean “his family members are all tall”. Note, however, that the usage of a plural verb after a collective noun denoting an institution (such as department, parliament, etc.) is much more widespread in British English than in American English; a Brit would likely say “the parliament are voting today”, whereas an American would say “the congress is voting today”.