Just depends on if each individual likes the color. If you like pink, why not wear a pink shirt? No different than any other color, except pink does have its unique qualities (hot pink especially - it's pretty much one of the most BOLD and BRIGHT tones of shirt you'll find, so if you dig bright colors, pink is right up your alley). I agree that it's kind of douchebaggy to wear a pink shirt just 'as a point' to look like you're really going against the norm, as the nonconformist don't-care-what-they-think rebel without a cause that you are...but if it's a color you dig, I say go for it.
I happen to like bold colors on occasion, so I have a couple of pink shirts here and there in the ol' closet because I like the color - like, beyond a standard pink t-shirt, I have one button-up shirt that's more of a salmon-ish tone, and I have another that's just totally bold and bright super hot pink. It's one of my favorite colors to wear every now and then, probably equal to teal - I have a cool really bright almost neon-ish teal shirt that I love and I put it in the same boat as the pink: it's something I like wearing every now and then because I dig the colors, but I don't over-do it in the fear of looking like a douchebag who just wears pink to go against the grain or whatever.