Marx's approach to history and sociology is materialist because it considers the various aspects of human societies (ideology, morals, culture, legal institutions, etc.) a consequence of the relations people estabilish to produce the material necessities of life (from the basics of food, clothes and housing to more complex goods and services).
Russell's quote refers to Marx's view described in the Theses on Feuerbach, which is a criticism of the Young Hegelians and their "contemplative" and "abstract" materialism. They saw themselves as external, impartial observers who analyzed and tried understanding men and their "essence" as if they all were speaking about the same abstract 'individual' (which Marx considered a form of mysticism), ignoring the specific historical and social context they live in.
Dunno whether he can be considered an eliminativist. That goes beyond my knowledge and/or will right now.
We want to live without dead time.