Skirts... Over pants

So I was walking down the street and saw several people in different places wearing skirts...over their stretchy pants.

WHY do people do this?? I think I was honestly scared.

I mean, I understand fashion statements, but this one is just not right. It's alright if it's a long skirt that goes down to the floor, because you don't necessarily see the pants, but I'm talking about miniskirts here. And most of the skirts are bright TURQUOISE and such ugly colors.

Where did it come from?

Why is it worn?

Either wear pants or a skirt. End of discussion.