It is wild seeing someone drink something labeled with the irritant, health hazard, and environmental hazard warnings. It also begs the question of disposal regarding the environmental hazard one. I know it's safe due to the doses, but made me pause in horror briefly. (Reality check: Many drugs have the health hazard, or even the skull-and-crossbones. But anecdotally, many of the health-hazard-marked substances I've come across are carcinogenic/reproductive harm)
The dose (often) makes the poison.
Citrus fruit itself is generally regarded as fine to eat. Concentrating the oils can make them irritating (and flammable, etc) but that’s essentially undone by diluting them into a syrup and then diluting the syrup into an actual drink.
If those kinds of warnings were required on naturally occurring products, pretty much everything in your pantry would need them.
A 28-oz cylinder of table salt, that can be easily had for $1 at a grocery store, could kill eight healthy adult men, if they each consumed a third of a cup in one sitting.
A five-gallon carafe of water used in most water coolers holds enough water to kill two adult men, if they drank it as fast as they could.
There's a bunch of foods that are poisonous if prepared wrong. I can't find the lethal dose, but a bag of raw kidney beans could kill multiple people. A cassava/tapioca root can kill you too. Eating a bottle nutmeg probably won't kill you, but it might make you wish it did.
Of course, it would be difficult to consume enough of any of these things to hurt yourself, (except for the beans) because we're able to sense when we are consuming dangerous quantities or types of foods, but it's not flawless, hence the need for tradition to pass down how to cook, or warning labels for foods that aren't prepared in traditional ways.