You might actually want to investigate that claim before you take it as truth. Many skeptical organizations have mission statements and therefore it is easy to determine the purpose for which they say they exist. Wikipedia has a extensive
list of skeptical organizations from which you can access the websites and read the mission statements or descriptions of such skeptical organizations as
Australian Skeptics, the
Center for Inquiry, the
Committee for Skeptical Inquiry,
Irish Skeptics, the
James Randi Educational Foundation, the
New England Skeptical Society, the Richard Dawkins Foundation for Reason and Science (its statement is forthcoming, but it is significant that it is planned), and the
Skeptics Society. While this is certainly not meant to be an exhaustive list or even a statistical sample of all skeptical organizations, it does demonstrate that a limited set of skeptical organizations hold certain goals in common despite being only philosophically connected. As I have said before, I am not trying prove that there is one single, centralized Skeptical Movement or that everyone who self-identifies as a skeptic belongs to a skeptical organization; however, when skeptics come together with the purpose of creating organizations and societies devoted to disseminating skepticism (a goal which I don't think is wrong) skepticism ceases to be an individual endeavor and enters the realm of group actions and social movements.
Given the above provisos about what I believe and examples of the goals of skeptical organizations, I don't understand why people continue to insist that there are no skeptical movements or that independent organizations do not somehow, in the abstract, represent a larger movement. It seems as if there almost some sort of benefit to stubbornly rejecting the sociological aspects of skepticism.