When did “fag” become an offensive word?

Question

I'm from Pennsylvania. With the recent threat by the Westboro Baptist Church to protest the funeral of seven children who perished in a fire, I've been thinking a lot about their infamous catchphrase: "God Hates Fags." Religious debates aside, when did "fag" become an offensive word?

Answer 1

According to the online etymology dictionary that I use, "Faggot" came into usage in 1914 and "fag" in 1921. Prior to that definitions included a bundle of sticks for faggot and cigarette for fag.

Answer 2

Fag, used with the meaning of "a male homosexual" has origin as short for faggot (1920s), which has then origin from the obsolete sense of fagot (contemptible woman).

_{[Reference: the New Oxford American Dictionary, third edition.]}