Stiles: “Are you gonna tell me you’re a fag? Because if you’re gonna tell me you’re a fag, I just don’t think I could handle it...”
Scotty: “I’m not a fag… I’m a werewolf.”
Within moments, Stiles is relieved and happy about this because, in this film, being gay is worse than being a literal lycanthrope.
In (the obviously already problematic as hell) Weird Science, the newly-empowered Gary hurls the F-word against an intimidating party crasher, as an indication that he is A Man Now. In The Wild Life, it is used about a ballplayer specifically because he has moved to San Francisco. In The Breakfast Club, Andy hurls the insult at John Bender.
1984's Sixteen Candles has aged terribly in terms of racist, misogynistic and ableist content, and so it comes as no surprise that the script is also littered with other-F-bombs. And yes, even Molly Ringwald's character Samantha uses it. Nobody comes out of this movie looking good.
Footloose, Pretty in Pink, The Monster Squad, and Heathers all contain the slur as shorthand to demonstrate the character uttering it is a terrible human. However, with the exception of Heathers—which contains an entire storyline about getting revenge for two jocks' raging homophobia—the slurs could have been replaced by any number of more generic insults.
Some filmmakers have since looked back in regret. There is a scene in Adventures in Babysitting, where Brad tells his little sister that her hero, Thor, is "a homo," which upsets her enormously. In a 2016 interview with LA Weekly, Adventures screenwriter David Simkins looked back on the line: "That one hurts me. I cannot tell you how much it hurts.”
Watching these movies in my formative years, growing up in the UK, I recall my sisters and I wondering aloud why Americans called each other the F-word so often. To us, "faggots" were a type of food and "fags" were slang for cigarettes. In our naivety, it seemed like a really silly thing to use as an insult. But it is doubtful at this point that there is a teen or tween left in the world that doesn't know the word's true intent. As Wikipedia explains: "Its use has spread from the United States to varying extents elsewhere in the English-speaking world through mass culture, including film, music, and the internet." These globally successful '80s teen movies undoubtedly had a hand in that.
Efforts have been made to reclaim the word in more recent years—the 2009 documentary Fagbug being a notable example. In 2011, Domenick Scudera wrote for the Huffington Post: "You have probably heard of other people reclaiming offensive language to remove the sting, and now it is the gays’ turn… I cannot do this alone. I need the help of all the other fags and their supporters." Other commentators simply don't want the word used at all.
Culturally, America has moved so far forward, homophobic terms bandied about in popular culture are impossible to ignore for most people, and utterly intolerable for others. According to the Chicago Tribune: "A 2014 Pew Research Center survey found 67 percent of millennials (anyone born after 1981) support same-sex marriage. (Gen X, which includes all of the Breakfast Club, is at 53 percent now.)" As each generation of teenagers becomes more socially progressive than the one before, what were once considered pop culture classics will simply become ever harder to stomach.