I think it's pretty typical for 6 year old boys to see no value or interest in coloring and rush through it. I know that my 7 year old still has trouble with the fine motor aspect of it, but he CAN color when he puts effort into it. He just doesn't care enough. I can see how it's a beneficial exercise for kids who are weak in fine motor skills, because it probably helps them learn to write neatly...but if that is not the case, it seems silly to push "neat" coloring.