Are you sure about that last bit with the monkeys? Most fruits contain fructose, it’d be weird if money body just discarded a perfectly good source of backup energy.

Also your liver can metabolise fructose straight into glucose too if needed. Obviously not as fast as eating glucose, but if you were a monke, it might be pretty useful. In today’s sedentary society it’s of course more harmful, but I don’t think fructose itself is inherently bad. We just live lifestyles and have diets where it has little to no place.