why?

Great question, though, I don't know the answer. I do believe that they taste different though, but I am not sure why. I personally do not mind if it's pink or regular lemonade, I like it both, so long as its not very tart. I prefer it to be sweet, but the color is not relevant.

I make pink lemonade out of pink grapefruit. It is still call lemonade even if is made out from different citrus fruit.

I like pink lemonade better, although I don't know why. It tastes more sweet I think, and a but less tart. Of course that could have to do more with the brand I buy, than the actual lemons themselves.

I like both, but I don't get to drink the pink kind very often.

Personally, I like yellow lemonade better, although the different juices used to jazz the pink ones are are tasty in their own right except for the grenadine which is more like drinking candy. For a tarter drink they add cranberry juice, but to me just putting in less sugar makes more sense. I don't like pink grapefruit juice as well as the regular kind either, but your point is interesting, for although red grapefruit is everywhere, it is pretty hard to find a pink lemon.