It's a much better word, the D in dick makes it sound softer and somewhat gentler, you start with a way less harsh sound, it's friendlier, you want to ask it to hang out for some beers. Cock starts with a C and and ends with a ck, it has a very powerful, sharp, noticeable sound, you can't ignore it, it's right there in front of your face whether you want it or not. Maybe you can't be friends with it, but you sure as hell knows it gets things done.
I have spent way too much time and effort thinking about this.