well the fiber recommendations are based on the fact that people just don't enough fiber and for some people 25g fiber is a big deal.
There is also a difference in the quality of fiber. Fiber from whole foods is a bit different than added fiber. I don't strive for a certain amount of fiber, it really just happens through my natural diet. I don't get get gas, bloating or diarrhea and I've never heard of any studies based on too much fiber, especially from whole foods. If you had any studies that talk about the dangers of too much fiber, I'd be interested in seeing them.
Too little fiber though is often a result of our 'industrialized' diets and a more natural diet naturally contains more fiber. If our bodies weren't built to handle the fiber in natural diets, I don't think we would've lived until the industrial age
I also get my blood tested every year and from my most recent checkup, my body is well nourished.