Q: Why can't I add something about this [case, arbitrator, editor]?
A: Content must be covered in reliable sources for inclusion in Wikipedia. Of the hundreds of Arbcom decisions and dozens of arbs, very few have made the news media.
Q: Why are some of the links external links when they should be internal?
A: Some of the links, such as to the Arbitration Committee page, point at non-mainspace pages. For the benefit of those reusing content, who don't copy the Wikipedia space, externally formatted links are used.