What's up with these upsidedown hats?

[Wig Twistin Season]

back then sports apparel was fashion, not fandom. If you had green sneakers you matched it up with a celtics jersey. Red sneakers with a bulls jersery and so on.
After a certain point, sports apparel sort've fell out of style and people kept to simply rocking the teams they root for.
Also they make enough alternates these days even if you root for the spurs you can find a green alt jersey if you really wanted.

Repped for accuracy.

It changed in the early 2000s to rep your city or team in multiple flavors. Few know Spike Lee is actually responsible for the different flavor hats and made New Era BILLIONS.