For those who don't have huge capital stocks and thus have little but wage labor to turn to earn a living, technology that competes with labor deepens their economic subjugation rather than effecting liberation.
Now, obviously, getting farther away from capitalism in the economic structure may change this, but that isn't an automatic consequence of the technology.
That said, if we imagine that there is productive marginal work to be done, then replacing drudgery with automation frees up the money being spent there to be spent elsewhere, and presumably increases demand for the better work.
Obviously there are some assumptions, and "liberation" may still be hyperbole, but it doesn't necessarily benefit only the capitalists.