A rights activist that strongly believes in equality and fairness. They generally fight issues regarding discrimination against a specific race, gender, or sexuality.
Justice crusaders are often found debating about political and social issues regarding inequality. Many tend to find racist, sexist, or other discriminatory intentions in places that did not originally intend to offend anyone by any means. They also commonly exaggerate the offense or take certain statements a bit too seriously. Unless you are also a justice crusader, most people find justice crusaders annoying.
A number of them are also very hypocritical. Justice crusaders are usually members of a minority, and they tend to target and criticize white people for their "white privilege" or "inability to understand." They do not realize that this in itself is discrimination; for they judge white people harder than other races and cultures. If you tell them this though, they will probably deny it; they defend themselves quickly and are usually angered easily. Trying to talk sense into them is difficult.
God, that girl is such a justice crusader. She always talks about how unfair white privilege is but always goes on about her Asian pride.