I'm old enough to remember when girls always came in pairs, they always had a "girlfriend" who they spent most of their time with. Men would use the terms 'best friend' or 'wingman' though loners were still fairly common among men, and rare among women.

In either case, platonic friendship is something that goes back as far as human history. It only had to become sexual when utterly depraved lunatics were running the asylum.

As usual: women most effected.