I've made a new video against low-carb diets

[LadyForCamus]

Yes, it would be unethical, and no, we don’t jump to a scientific conclusion in the absence of better information. That’s the opposite of how science works. We say “we don’t/can’t know for sure.” Especially considering the fact that not everyone with elevated LDL levels will eventually develop heart disease. That’s why it’s not scientific to say “food X causes disease Y.” We normally say nutrient X can raise bio markers that are associated with certain disease risks. If I eat one coconut, will I develop heart disease? Two? One a week for six months? Three a week for six months?

If we say "We don't/can't know for sure.", then we basically say we do not know anything, since there is hardly anything in science we know for sure.

No. That’s a false dilemma. In science we say as much as we can say based on the evidence we have, and we don’t say more until we have evidentiary support for it. In this case, we can make reasonable inferences based on the available data and use them to set guidelines for saturated fat intake, but what we cannot do is say “coconuts cause heart disease.” 

What do you mean not everyone with elevated LDL levels will eventually develop heart disease?

 
How was that ambiguous?

That is, as far as I understand it, true only because there are other causes of death, such as cancer and car crashes, that might kill us before we had a chance to develop heart disease.

Without a crystal ball, I’m not sure how any reasonable, evidence-minded person could make such an assertion as “they would have developed heart disease if only they didn’t die in that car crash.” How could anyone possibly know that? Have you any idea the myriad of factors that play a role in disease manifestation and progression? It’s not just one bio-marker.

But one cannot live into the old age with elevated LDL levels, right?

Of course they can. I was a clinical dietitian at a nursing home for several years. Almost every one of my residents had dislipidemia, lol. 

To be frank, I don’t think someone who still has so many questions (and I’m glad you have questions; that’s how we learn) should be posting YouTube videos from a place of self-ascribed authority on any of these issues; especially with the audacity to call opposing views “obvious nonsense.” I encourage you to take some courses in nutrition and dietetics if you’re interested in the subject, and spend a few years learning before making further clinical declarations about medical nutrition therapy and posting them to the internet.