But is it a movement? A movement implies organization. There is no organization. If there are autonomous groups, maybe those have organization.

I won't say the Wiki is wrong, but I'm skeptical. Albaby has (IMO, correctly) been arguing that it isn't an organization. It's, at best, an attitude or idea or position. Can it be a movement without some form of organization?

Yes, it is a movement. But it is not an organization.

I think one possible source of the confusion is the fact that "organization" also has several meanings. It can refer to a discrete organized entity ("The Sierra Club is an environmental organization") or a characteristic or trait of being organized ("The Civil Rights Movement was marked by high levels of organization.")

So a political movement - a collective effort by a group of people within a society to achieve some form of political outcome - can be organized or disorganized, but the movement itself is not an organization. For example, the Civil Rights Movement or the Labor Movement or the gay rights movement or what have you. There were lots of entities - organizations - that were involved in those movements, but those movements were not themselves an organization.

Turning once again to the example that Dope has cited, there was a movement in support of Irish Republicanism. There were many organizations that were involved in that movement (the Provo IRA, the INLA, a dozen or more splinter groups or offshoots from various incarnations of the IRA, etc.) - but "Irish Republicanism" was an idea and a political movement, not itself an organization.