Who's right? They both are.
How do you group things like the Penny, Vietnamese art, ancient writings, and all the myraid of items at the Museum? There's just so many ways of doing it, all providing perfectly fine classifications, but which may appeal to some people more than others. For a more mundane example, think of all the different ways you can organise your music collection (I have the honour of being called a freak by Jo Whiley about the order of my CDs, so I speak with some authority). You could do it alphabetically, by title or by artist. There's a chronological option, either by release date or purchase date, thus providing snapshots of music of the time or the music you were listening to respectively. You could group by the movement that a band belongs to (Britpop, post-rock, pop, and so on), or simply by the colour of the album. Each classification provides a slightly different view of your music collection, which also seems to alter your reaction to your collection (an album that may have been swamped in the alphabet classification may stand out when albums are organised by year, for example).
The problem is that changing these classifications is normally a tough job. Computers, however, allow us to change our view of things on a whim. The Internet Movie Database is a great example of this. Looking at the entry at My Fair Lady, we get reams of information about the film, but it has links which make us look at the film differently. With one click, we can see how it releates to Audrey Hepburns's career. Another click shows us that is part of the latter part of George Cukor's directorial life, whilst yet another click takes us to a list of films released in 1964. Completely different ways of looking at the film, which would require major physical upheavals in the real world, but extremely simple given a computer and a hypertext system.
Erm, yes. No, I don't get out much. Why do you ask?