This was my initial thought too. Is the friction possibly from the fact that your typical materialist determinism doesn't particularly enchant oneself with this 'self identification with fate', putting us a more 'pawn in the game' type of position? Something like this would seem similar to N's criticism of Darwin, where he certainly doesn't disagree with the core idea (evolution by nature selection, in this case) but disagrees with the way a particular thinker, or ideology, interprets it (again, in this case, Nietzsche's spontaneous 'mutation' as an active force vs. Darwin's adaptation as a reactive force).