"gay" is not a slur unless you use it in the wrong context. Before it used to mean "happy" back in the good ol days, now we use it to describe same-sex marriages.
I was the same. Growing up was pretty rough. People would often use LGBTQIA+ terms in the wrong way to harass each one another. We didn't understand gender biology or expressing because when I was around, the 2016 election came up, and things were taken in a different manner.