Plants, poorly sealed wet acid batteries, and athletes all have this one crazy thing in common; click the link to learn more

Again, if you're actively exercizing, that's not an issue. But this post demonstrates that most people view it as a general purpose drink.

Cutting the Gatorade with water once about 1/3 is drank helps a lot

Whether or not the shittonne of sugar in Gatorade is a problem depends on the person. A lazy Google search tells me professional athletes require between 3000 and 8000 calories, obviously depending on what sport they are engaged in. They could probably use the sugar; they're probably pounding protein shakes too, and you can't get all of your calories from protein long-term, you need sugar or fat or ideally both.

Then there's alcoholics using Gatorade for hangover recovery. Alcoholism tends to reduce food intake, causing alcoholics to frequently be underweight. Sugar in the default hangover drink isn't hurting them, they probably need it, and could probably use more calories besides. I know, this one is me. My license says I'm 5'9", and the scale just told me I'm 108 lbs. With a BMI of 15.9, any calorie I consume is a good thing, regardless of whether it's dextrose, sucrose, a complex carb, or protein.

Inactive people who eat more than they need and are overweight because of it don't need the sugar in Gatorade, but also probably aren't active enough to need the electrolytes in Gatorade; they should be drinking water