McCarthy's accusations of communism were similiar to the accusation of witchcraft in Salem. This inspired The Crucible because Miller is trying to explain the Theme Preversion of Power which McCarthy had done. Basically he abused his power. This is much like McCarthyism because people are being accused without any evidence.
It is the opinion of a person that one gender is better than the other. The person that is being discriminated is deemed worthless. People saying their gender is better than other's gendrr.