Pretty much everyone in my junior high said it. It was one of many go-to insults, not even really thinking about what it meant. Like douchebag. I didn't know what a douchebad actually was until I was probably 15 or 16. I just said it because everyone else in junior high did.
Later, in the 90s, it was a little different. I had gay friends who were really cool and we'd hang out all the time in a mixed group because cool people are just cool people. But all of us found it annoying when someone acted flamboyantly gay (and we also hated people who were flamboyantly straight too, those idiots who have to be sexist shitheads and act like men>women and women only exists to please/serve them).
So calling someone 'faggy' in the 90s was a telling a guy he was acting like a flamboyant homosexual putting on a big show of being effeminate. For example, for my honeymoon, my wife and I went on a Disney cruise. There was a gay couple there we'd bump into from time to time. One was the over-the-top complaining like a rich Long Island housewife over every little thing, and the other one putting up with his bullshit.
Case in point, we were on the beach and flamboyant-guy was on an inner tube slowly drifting away from shore saying, "I'm just gonna float out into the middle of the ocean and you're doing nothing about it, just leaving me to die...." And the not-flamboyant-one rolls his eyes, takes four steps over and pulls him back toward shore. So in the 90s, we'd say the over-the-top person was 'acting faggy' and the other one was just a cool dude who was gay - not putting on a big whiny show. The same could be done of two dudes where one is cool and the other goes on an on with "And I'll bang that chick over there at the other end of the bar and finish on her face then throw her outta the car and call her a stupid whore...." blah blah blah.
In the 2000s on, people have pretty much stopped using these terms (in my age bracket). However, the other guitarist in my band is a lesbian, and real cool person and I've heard her call things "gay" a couple times - with the old meaning from the 80s. Like when you were hanging out with your pals back in the day and you're bored, and one would suggest, "Hey let's go to the library!" and everyone else would go, "No way. That's gay. Let's go hit rocks with baseball bats into the neighbor's pool." Like the N word, I leave the G word, the F word and the Q word to the people who own it and embrace it. I don't want spread any hate with tired old insults.