I'm not sure if you're being sarcastic and pointing out that anything is "toxic" in high quantities. In case you aren't, or for people that did not catch it, 29g/kg is about 2.4kg of sugar for the average 80kg male, which comes out to about 12.5 cups or 3 liters. It should be obvious to most people that filling a two-liter bottle with pure granulated sugar and consuming it in one sitting would have severe health consequences (if you can even manage to get it all down).

What's probably toxic about it at this dosage is that it cannot be eliminated by your kidneys or stored in your liver quickly enough, so it accumulates in the blood and shifts the osmolality causing neurological symptoms, osmotic diuresis and cardiac arrhythmia.