The tricky thing about fruit is that our loss of the fourth phase of endogenous vitamin C production occurred at a time concurrent with heavy fruit intake. This clearly offset the unfortunate effects of this loss. I've seen a lot of paleo types claim that you get plenty of vitamin C from liver and meat (I guess they eat both raw) and that vitamin C from fruits etc. is unnecessary. Incidentally, I've also seen a lot of paleo types say that they've gotten bleeding gums. Clearly, vitamin C is needed as an antiscorbutic as well as it's many other functions.
Now, even if we accept that fruit contains compounds that are beneficial for human health, we should also accept that they contain a poison in the form of fructose. A mistake that is often made is assuming that because ancestral humans did a particular thing, it must then be optimal for humans under any circumstances. Our environment, and specifically our constant abundance of food, has given us an "out" as it were with regard to fructose. If an individual has a marginal caloric status, then that fructose could make the difference between thriving and wasting away. I dunno about you guys, but I never have a problem getting enough calories to the point where fruit needs to make up the difference. The same could be said about the consumption of honey. For them it's a net benefit, but that's not the case for us.
The author's reference to the sugar ratio of berries is odd, since it's not the ratio but the dose that we are interested in. Raspberries have very little fructose, but quite a lot of fiber, vitamin C, and manganese. I enjoy eating them and don't feel as though doing so is an act of asceticism.
I'm principally concerned with optimal health and longevity, not eating enough to stay alive for the near future as my ancestors likely were. Contemporary HGs or anatomically modern humans of the past didn't need to worry about something like glycation because the odds of that being the deciding factor between living and dying would have been highly unlikely. Who knows, for me it may come down to that. If I don't feel like I'm missing out by not eating super-sweet fruit, and I'm getting the nutrition elsewhere, then I don't see the problem. I know that fructose from fruit can be metabolically damaging because I've experienced it in the past. I've seen my TGs drop dramatically as my fructose intake has decreased and as much of a cliche as this is, I've never felt better. I've found starch to be far superior for peri-workout nutrition compared to fruit.
I suppose I'd have to see a more compelling argument either that fructose is somehow healthy, or at least completely not harmful, or that there is a substantial amount of nutrition that I'm missing out on by only eating berries. If I were really addicted to sweet tastes and this came down to a quality of life issue, then I suppose it would be worth it, but I'm really not sitting here fidgeting thinking about eating pears.