Warren, it was done because visitors see the front page when they visit the forum. Clutter was one of the main reason, and its one of the reasons for categories - to reduce clutter. A few categories show on the front page and other ones are not. The meta category is not part of the central forum, but rather a category about the forum itself.
Many forum programs only show the categories on the front page. Discourse allows a selection of new posts to show on the front page and the categories are accessed from a pull down list.
If you honestly feel that the community wants meta back on the front page rather than a click away, then do a Poll and let us all see if the community supports (or not) the community members who suggested it, which the forum admin agreed was a good idea.