Color Exclusion: Choose what color(s) is/are to be removed from the image.
By choosing from the color pallet, you can choose a single or multiple color that would be excluded from the image. For instance, if you had a red background then you can choose the red color and have it removed completely without having to deal with the other tools. This makes it faster and easier to remove backgrounds of pictures of high contrast
AdminJacob N (Admin, Clipping Magic) commented
I'm not entirely clear on what you mean here - did you get a chance to review the tutorial? http://clippingmagic.com/tutorials/basics
Adding the UI and cognitive complexity of an additional mode of usage would be prohibitive - just put some red marks on the colors you don't want?!