Occupy Wall Street are just ordinary people who want their voices to be heard by the government, major corporations and anyone else major. They are also peaceful, they don't use guns, explosives or violence, unlike terrorists. Why would they be branded as terrorists, they only protest with signs and maybe slow traffic at the worst.
For the most part, Occupy Wall Street folks are not terrorists, although of course a few might slip out of the boundaries of quiet protest. These are the people we want around, who are looking at the government and the system and giving their critiques. They have to make their voices known in some way or the other.
I don't think that it would be fair to classify them as a terrorist group. While there are some bad apples that do terrorize communities at times, I do believe the majority are just a group of misguided youth that want to make their voices heard. In my opinion they do have a point, but their message is often disregarded or lost, because of the way they deliver it.