The general consensus between actual users seemed to be that the fumes were obviously toxic and you should avoid breathing them in. However, there were always people who denied this, and I've never seen a manufacturer warn users about the fumes.
PTFE fumes though...
In practice though, the study shows PLA is safer because of significantly less fume creation with the lower printing temperature.
So relative risk for PLA is significantly lower than ABS, but it is incorrect to state that PLA is less toxic.
https://en.wikipedia.org/wiki/Odor_detection_threshold#Odor_...
You listen to your other senses, right? When you touch something hot, you listen to your sense of touch telling you that you're about to get burned. That doesn't mean your sense of touch can warn you of all hazards, but you certainly shouldn't ignore it when it does.
Farts smell. Carbon monoxide doesn't.