I voted 'yes', but why should bitcoin support alternative currencies? If alt coins only value is riding the coat tails of bitcoin, maybe it isn't such a great alt coin.
Because this is a forum, and you would want to take all the pageviews/visits that you can get. Even from alternate cryptocurrencies so you can sell your advertising space more.
On the same note you could also argue of why there is an off topic thread...
This if a bitcoin forum, Wether we like it or not BTC goes hand in hand with LTC and the rest. So why not make it tidy?