Unless my perceptions are way off, there's a whole lot of sarcasm going on here.

As someone who gets the World Almanac for Christmas every year, it's safe to say I really like lists. I also have titles like 'The top 10 of everything' and 'The big book of lists' in my bookshelf. I also like tables, rankings, charts, graphs, etc. I'm a technical thinker, so I find them fun to think about. Is it a relatively pointless exercise with music? Sure, but that doesn't stop every music webpage I've ever seen from being full of 'rank the albums by this band' threads.
Why do people do it? Because it's fun. It's another way to think about and get something out of music you've heard 100 times over. It's a way to share your opinion and talk about something your passionate about. If you don't find it fun, don't participate in it. I'm not familiar enough with whomever this thread is imitating, but clearly there's a notion of his/her silliness in ranking things. Well, I don't know enough to say anything about that person, but as someone who just posted a 'ranking' thread, I can't help but be a little insulted.