What do the parents you know say when you tell them that they're medicating their children for normal human emotions? My guess is that they could give examples of things that aren't actually normal which caused them to seek out a professional in the first place.

In previous generations children with corrective lenses were rare, and kids used to fear being made fun of and being called "four eyes" for wearing glasses to school. Recently it's gotten a whole lot more common for kids, even toddlers, to wear glasses. It might be tempting to think that Big Eyeglass was treating people for normal human blurriness, but it's more likely that eye glasses, and eye care more generally, has gotten more accessible and that more kids getting the care they need and recent environmental factors are contributing to the increase in kids needing glasses (and needing them at younger and younger ages).

It's the same with mental health issues. We have increased awareness of mental health, reduced stigma around seeking and receiving treatment, improved treatments, a better understanding of various conditions and how to diagnose them, and recent environmental factors that may be exacerbating problems if not inducing them.