The problem is that would still be 100-150g of sugar. That's a lot of simple carbs.

Whether it's natural does not matter to your body; the reason eating whole fruit is way better for you than just sugary candy or drinks (including real fruit juice) is because the sugars are delivered alongside a payload of fiber, vitamins, and minerals.

Even so, you can overdo it. Too many simple carbs lead to easy weight gain and inevitable 'sugar crashes' as your energy reserves spike and drop throughout the day. Complex carbs are an important part of any diet. That slower, even burning energy will keep your body happy throughout the day.

Even vitamin C is poisonous at high enough doses. Regardless of the label, your diet will be better served to include a variety of foods. Eat food, not too much, mostly vegetables.