There is confusion both among lay-folk and scientists alike about the difference between statistical significance and importance. A study could demonstrate that eggs have a statistically significant negative impact on some indicator of health, and the media would relay it as "eggs are bad." Meanwhile consumption of eggs is like the 5,000,000th most important determinant of morbidity. Then the discussion devolves into "my grand-daddy ate 2 dozen eggs every morning and lived to a hundred." OK... so what? Some things are only a tiny bit bad, it is not like someone is going to discover the diet of the 5 magic best foods that make you live forever. If you do not smoke and you maintain a low body fat you will
probably live longer, everything else is YMMV, take it with a grain of salt (unless you are hypertensive).
Not everyone realises that science is, in fact, a social discourse. It is not objective. It is not fact. It is not ever 'done'.
On a philosophical level I agree with you. On a practical level, come on, it's the best we've got! Sure, there will be better ways to make fire in the future, doesn't mean we have to be content with banging two rocks together until the field is 'done'
However, this also fails to account for the fact that some scientific disciplines are extremely objective. Take chemistry as an example, I can write you a protocol that says "If you mix 1 mol of A with 1 mol of B you will get 2 mols of C." and you can go off and do exactly that. That protocol could care less about your cultural background or the like.
In my experience, published chemistry is something like 50% objectively true, 35% mostly true, 10% misinterpreted, and 5% completely fabricated. That is still better than many other disciplines. I imagine maybe something like anatomy must rely heavily on objective fact. You will not win too many arguments with "that I have both a right and left leg is a matter of opinion and perspective."
Also, getting back to OP's wife, at some point carbs are as addictive as cigarettes and alcohol. Basically if the pancreas and body cells are having issues with insulin, the blood sugar is on a roller-coaster and when it crashes, the person craves more carbs to get their blood sugar back to normal.
I always wonder if people who claim to need a lot of carbs have ever tried substituting high carb veggies like beets or sweet potatoes. I think the object of the addictiveness is not carbs in general, maybe a combination of salt and oil and simple sugars. Easy test would be to eat a whole baked potato and see how it makes you feel. Then try eating a pack of dried seaweed. Which one is more addictive?