How does the judical review protect the rights of the minority?

It protects the rights of the people because it keeps the legislative and executive branches from giving themselves too much power. If they had to much power then we wouldn't have a constitutional government. The rights of the people would be in danger. They can declare any law that violates the people's rights unconstitutional.

Since, in general, the majority rules, it is possible for the legislative branch to make laws that unconstitutionally deprive minorities of rights guaranteed to them under the Constitution. The Supreme Court uses its power of judicial review to declare laws unconstitutional if they violate those rights.