If you click through to the actual law, its weird in terms of the categorization since it doesn't use any of the standard rubrics. The rule applicable to roads with more than two lanes in the same direction is neither a "left lane for passing" rule, or a "yield left lane to faster moving traffic" rule or a "must keep up with normal speed for the road except in the rightmost lane" rule. Its a "you must always drive exclusively in the rightmost lane no matter how many are available, unless there is 'substantially continuous' traffic in the lane, or you are using the left lane for turning."
It might be straight-forward and sensible (that, particularly the latter, is particularly subjective), but its very distant conceptually from the rules commonly used elsewhere that form the basis for the categorization and thus is, in context, weird.
