Our digestive systems have variability from person to person. Fiber can improve constipation in some people and actually make symptoms worse in others.
People from cultures that have developed with low fiber diets, generally have digestive systems that do better with low fiber, just as those that developed in dairy free environments tend to have a higher incident of lactose intolerance. My assumption is that even the traditional Inuit diet had some seasonal plant matter, berries, seaweed, etc, which are high in fiber.
You just have to figure out what works best for you.
I barely ever have constipation and I dont eat more fiber than anyone else I know. I feel like it depeends on something else, not the amounts of fiber. I also never ever eat supplements and I am not more sick rhan those who take them regularly. Only time I took them is when I was pregnant.