> If I am correct in thinking that the <l>...</l> element has the same
> behavior as <div>...</div>, why not remove BOTH from the specification and

That's a presentational argument.  XHTML2 features have to be justified
on primarily structural grounds.

> use <container>...</container> (or some other appropriate word/abbreviation)

I believe the intention is that <l> should not contain any block level
elements, whereas <div> normally only contains block level elements.