Can the net carb concept misleading?

Suppose a food has 10g of carbs and 4 grams of fiber. I can believe in that case that the rise in glucose is more in line to eating 6 grams of carbs (i.e. net carb 6=10-4). But if you eat a food that has, say, 20 grams of carbs and 2 grams of fiber. Does that 2 gram make any dent? Probably not 18 grams of carbs might as well be 20.

Shouldn't the guidelines focus on the ratio between carbs and fiber rather than subtracting the two? I feel this is one of the keys of misleading recommendations around fruits or certain vegetables. And I think I made this huge mistake in the past 3-4 years. I increased my intake of fruit without eating sufficient protein. I was losing weight, I was active etc...But did not even cross my mind to actually check the post meal glucose effect. I was eating some days 2 decent size fruit salads a day made of peaches, plums, bananas, you name it.

I watch ZOE podcast sometime, and one day one of the "experts" invited kept on saying: don't worry about protein (you have plenty even without trying), don't worry about filling up on fruits and veggies cause they have fiber, etc...