"the visible wavelengths required significantly lower laser exposure than near infrared wavelengths to disable subjects, though near infrared sources remain attractive given their cost and retina safety"

The paper repeatedly claims near infrared laser light to be "retina safe" (quotes theirs) which is an oversimplification. Infrared light of wavelength around 1 µm in sufficient powers is very dangerous for the retina, especially compared to visible light where the blink reflex can save damage by lasers up to a point. Telecom wavelengths around 1.5 µm happen to be safer because such light gets absorbed in the cornea before being focused onto the retina, but at sufficient powers or longer wavelengths (e.g. 3 µm) where the absorption depth in the cornea gets very short there can instead be damage to that part of the eye. It's always the combination of the wavelength, which determines the absorptivity in the different parts of the eye, and incident energy (pulse duration × power), that determines the safety; there are no innately safe wavelengths close to that part of the spectrum.