There are definitely those that are so negative about nearly everything. They are poisoning the well. Why are they still there? It's no secret how negative they are. It hurts morale, and they influence others around them in a negative way.
One department head (where a lot of the negative employees are) seems to always be on a witch hunt looking to place blame on anyone else if something goes wrong, rather than working together to find a solution. (CYA mentality)