Are they? People in the US, at least, consume far more soft drinks than lemonade or orange juice. For that matter, they consume nearly twice as much soft drinks as beer.
Some of what you're perceiving might be due to age. Kids usually prefer very sweet things; as we get older, we develop more of a taste for sour or bitter. I've been slowly decreasing the amount of sugar I put in my coffee,though I'm far from my parents' taste for black coffee (i.e. no sugar).
And culture, of course. As I noted in my India book, Indians like Coca-Cola... but think it's improved by adding spices (lemon, rock salt, pepper, and cumin).