The word fag is used mainly as a derogatory slur against gay men, but it has other, more benign meanings as well. For instance, it means a bundle of sticks (like kindling), and in British boys' schools it can refer to a servant who helps older boys with their chores. It is also a slang term for a cigarette in some countries. A common etymology connects the use of fag as an epithet for homosexual men to medieval Europe's practice of burning people at the stake for heresy or witchcraft, but that etymology is based mostly on speculation and lacks evidence.
While it may be tempting to focus on homophobia as the explanation for why are gay people called fags, that explanation obscures the powerful relationship between masculinity and this type of insult. The fact that boys aggressively tease each other with fag talk and imitations indicates that becoming a 'fag' has as much to do with failing to meet the masculine demands of competence, heterosexual prowess, and strength or in any way revealing femininity as it does about sexual orientation.
While research on gay men's experiences with slurs and teasing needs to continue, the recent work of scholars like Orenstein and Pascoe points to an alarming fact: Most people seem unaware that fag is an epithet and not an innocent or even neutral term. That ignorance is likely to be more pronounced among those who are the most active opponents of equality and anti-discrimination.