You've always been tolerant of people from groups other than your own. It's just how you are in the world. Even from a young age, Aquarius knows how to be broad minded and tolerant of all kinds of people.
You're not friends with everyone, of course. Some you just don't vibe with. But if you had your way, you'd at least have some sort of shared human connection with every person on the planet, validating your mutual needs.
Since your sign needs to have equality in all things, you use that broad mindedness to fight for fairness wherever you are.