Reduce clutter? Maybe you want to only remove some but not others?
Let me turn the tables on you -- why doesn't Google have a button to delete all of them at once?
A guess: They build a model of you as a customer. If you delete some information step by step then you possibly start with what bothers you most. So you do the data cleaning for them and train their algorithms. Not to mention that deletion is most likely just "hide this".