Competition is a good thing. There's room for multiple successful crypto currencies, and competition will weed out the ones that have flaws.
The problem is most are just clones of BTC that really offer nothing new.
The ones that offer nothing shouldn't gain much traction and will die off. I haven't invested any time or money into the alt-coin currencies, but I don't see them as a threat either. It is possible that some will provide good concepts which can either cause the currency to take off on its own or the benefits could be added to BTC in the future.
I don't see them as a threat either. There are definitely some good concepts out there.
I'm just trying to stop people from wasting time/money on new cryptos. A lot of newbies don't know better and will end up doing it, I just want to help people by giving them a warning.