You must have some great doctors to ask questions like these to. In my experience there's nothing cutting edge about any answers I ever got from a doctor, and more often than not it's a predictable, nothing-to-see-here attitude. And I learned long ago to be cautious when I say something like, "I was reading about a study that suggested..." as you risk getting pinned with the loons at worst, and mostly ignored at best.
I’m not sure my doctor has access to better studies than what is in the TFA. My question is weirdly formulated, what I ask is is supplementation useless given what we know? Or is it safer to stay in the (arbitrary?) recommended range? What I get from the parent post is that given low vitamin D is a symptom of poor health, supplementation is useless if someone is in good health.
The thing with vitamin D supplementation is that, as TFA mentions, low to moderate doses (under 4000 IU per day) are generally very safe. And, being deficient in such a crucial nutrient certainly isn't a good thing. So, if you are deficient, supplementing in that range is probably something you could feel comfortable doing on your own. If it were me, I'd go out and buy a bottle of D3 and get my levels tested at my next checkup.