The rationale behind the argument is that a person can become so offended or outraged by the sexual or romantic interest of a homosexual that he or she is driven temporarily insane and commits an act that would not otherwise be of his or her character (such as murder). The defense is often criticized as being illogical, offensive, and based in ignorance.
The defense is often used in the United States of America, especially in Southern states, where disapproval of homosexuality is very common. It is believed that this defense's effectiveness is boosted by widespread social fear and disapproval of homosexuality.
This defense was used in the famous case against the murderers of gay bashing victim Matthew Shepard. The two accused claimed that Shepard propositioned them, and they were enraged to the point of violently murdering him. The use of the defense was successful in securing a conviction of Aaron James McKinney for second-degree rather than first-degree murder, but its use enraged many residents of Laramie, Wyoming, where the crime took place.