I would say that the “left-wing movement” is precisely a typically eclectic trend, as it is a set of completely incompatible concepts. Here you have freedom of expression and political correctness. The absence of exploitation and high taxes. The right to work and war against strikebreakers. Freedom of conscience and sharia. The dictatorship of the proletariat and parliamentary democracy.

Similarly, anarchism is eclectic if considered without specifying terms via hyphens. The only thing all anarchist trends have in common is the indication of the possibility and desirability of liberating society from the state. Otherwise, anarchists have a complete muddle, from “property is sacred” to “property is theft,” from apologists of the labor theory of value to marginalists, from those who see the basis of all prosperity in the division of labor to those who see in it the root of all evil.

Anarcho-capitalism can be quite clearly depicted as the intersection of sets. You know, all those circles with shaded areas, reminiscent of the currently fashionable multicolored blobs. Everything that does not contradict economic theory is taken from anarchism, and everything that does not contradict the NAP is taken from capitalism. The result is a quite coherent doctrine, practically cleansed of eclecticism. This is easily verified: ask the same questions to a wide variety of ancaps, and you will receive answers that are very close in content. Such a trick would not work with eclectic doctrines.