Pink lemonade

Whenever we dine out and I'm not having a glass of wine with dinner I order lemonade. Pink Lemonade to be precise. That request sometimes gets a raised eyebrow, especially if I enthuse over it in the ordering process.

So tonight we ate out at a very cheap place, Village Inn. And I asked for a Pink Lemonade. The waiter said, 'we don't have pink lemonade, we've only got strawberry'. 'Well', said I, 'that's pink isn't it?'.

Maybe I've missed a subtle nuance in the language but, given that all the Pink Lemonade I've drunk here has been strawberry I'm not sure I understand why the waiter responded as he did. My wife also doesn't understand why. *shrug*