Anonymous, I suspect you're trolling, but giving you the benefit of the doubt I think it's completely false that you need to know PHP, SQL, or even good XHTML to use WordPress. If you continue to post the way you have been under an anonymous account I'm going to moderate your posts as trolls. If you have something constructive to offer, maybe you should think of a better way to phrase it.
Next, to clear a few things up. First, this discussion started around the use of an unordered list for the menu in the admin area. 99.9% of users are never going to change anything in wp-admin, much less look at the code, so I don't see why it's particularly relevant why we code one way or another.
Why is it coded the way it is? It's practical as well as political. WordPress is centered around a number of beliefs. One of these is that the application should follow widely accepted web standards. Second is that the administration should be accesible to everyone, be it someone with a screen reader or on a text browser like Lynx. Don't think this will never apply to you just because your vision is fine and you always browse graphically. Have you ever posted from a handheld device? Think you might in the future? The way the code is structured it's pretty easy. We don't rely on javascript for basic tasks, there aren't useless images everywhere, etc.
In addition to everything I've just said, there are some fiercely practical reasons the administration interface is XHTML/CSS. It's fast. Really. Most pages are only a few K, loading extremely fast even on slow connections. Having the menu as an unordered list makes it a lot easier to style things like we do, and adds a lot of flexibility if anyone wants to make alternate stylesheets. The menu *could* be images without changing one lick of the markup. The link mike offered is a great example of some of the things that can be done to lists just by changing the CSS. Doing similar effects with images and javascript would take longer and be slower to load and execute.
As has been said before, the better the markup is, the easier it is to style things. The more it can be leveraged. The cleaner things are when you need to make changes later. Sure there are poli-philosophical reasons for using web standards, but if those don't float your boat there are hundreds of practical reasons to use them. Ask Wired, Fast Company, ESPN, PGA...