Why does it matter what color a girls "lips" are?

In general, no, it doesn't matter. Some people have preferences but I know of no guy who ever said "no" because of labia color.

It has never mattered to me. I think men who say that they only want pink just don't understand that the color doesn't make up who you are. I've been with women with dark and lighter colors and they were both beautiful and enjoyable.

I think guys are tuned into whatever turns them on, so if they think you would look sexy in a certain color, they would probably tell you they prefer that color. It's the same thing with clothing, hairstyles, etc. Whatever they think looks best or turns them on the most with a girl is probably what they will say she should wear. It's because they want to be turned on by you, and they want you to do whatever it takes to turn them on - wearing certain colors of lipstick, clothing, etc. They also want you to want to turn them on and believe that if you like them, you will want to turn them on, so you will want to please them by trying out what they are saying. Make sense?

I don't think the color really matters

I believe you are referring to the "lips" below the waistline, yes?

I saw that comment in a previous answer too. I don't think that guy knew what the heck he wanted. Those lips, like the ones on your face are dependent on your skin tone. You can't change it and it is relative to the level of melanin pigment in your skin.

Don't fret about it.