The altcoin sections are very popular, so I'd like to support them. I don't think that they do anything to hurt the other sections. If you're annoyed at how they clutter the "show unread posts since last visit" page, then you can add those boards to your ignore boards list. (I'm thinking of changing this page so that you can click a button next to each thread to ignore the board it's in.)

I'm not usually interested in altcoins myself, but I can see how people can enjoy them. Most altcoin "investing" is a lot like gambling. I can see how trying to navigate and manipulate these tiny markets could be fun for a lot of people. These pump-and-dump altcoins aren't really competitors to Bitcoin: they're really a way of using your bitcoins to gamble. There are also a handful of technologically interesting altcoins like Monero, which I think are very useful for testing new ideas that might one day be incorporated into Bitcoin.