That is the perfect illustration as to why this pie should not exist. ANYTHING that is a pie should not need the volume of sugar that is needed in rhubarb pie. I just looked at 10 recipes and the smallest amount of sugar needed was 1 cup. Most called for 1 and 1/2 cups. This is in addition to the sweet fruits that you include with it (strawberry, cherry, blueberry, etc.) This should tell you that it is bad. Anything that needs tasty fruit to cover up the nasty weed taste should not exist.
Apple pie on the other hand averages only a 1/2 cup of sugar and needs nothing to cover up nasty stuff. Because there isn't any nasty stuff in apple pie. It is the best non cream pie...EVER! Coconut and banana tie for the best cream pies.