I would point out there is no contradiction between sugar not filling you up and being able to consume lots of it, and the fact that sweetness obsession is unnatural. (Citing evolutionary ancestors that lived on sugar is completely irrelevant.) I'd encourage anyone to give it a try - cut out sugar/sweets entirely for at least a couple weeks. It's not purely theoretical, and it's certainly not wrong in that sense, as it was helpful in turning my health around.
You are all over the place with this one. If you would drop the whole natural thing, you would be right.
Sugar does not fill you up, it just provides a lot of energy and is easy to store as fat for later use. You can eat a lot of it.
and the fact that sweetness obsession is unnatural
That is a vary confused way to put it. Feeling a strong desire to eat sweets and suffering withdrawal symptoms when you don't have any is "unnatural" in a way. It's more accurate to say it's indicative of a medical problem.
However just having a taste for sweets and wanting to eat them is perfectly normal and natural. This goes all the way back to anaerobes a billion years ago. It has ALWAYS been a survival trait, except in carnivores far removed from any herbivorous ancestors.
(Citing evolutionary ancestors that lived on sugar is completely irrelevant.)
That depends. To show eating sweets at all is normal, I think it is quite relevant. However it would be irrelevant in denying sugar dependency. Of course since nobody is doing that, your bringing it up was probably irrelevant.
As for the last part, you are completely right, but it has nothing to do with natural.
I think the problem lies in you needing to distinguish between a natural desire for sweets, and having actual physical cravings and withdrawal symptoms. That is a very very ginormously massive difference.
I don't want you to take this next thing as a personal attack. It's really more of a constructive FYI.
I notice that you tend to group similar things and treat them as being equal. for example, you have a category of things that is being discussed. There are 2 sub-categories. There are a few items that fit in each of the two subcategories. You will use any item in sub-category A interchangeably. You will do the same with B. I'm not sure if you put things in these categories to keep track of them and then no longer understand the meaning of each individual thing. or if your mind works only in broad categories and you don't understand any more granular differences. I just have to wonder if you write a sentence and think it means something very different than what it actually means.