it's something he has said many times, and now he's saying it about the french revolution because he's addicted to negative attention. it's the same childish vibes wizard bullshit he applies to everything bc it's his one unique contribution to The Discourse lol
Not like ENTIRELY though, he just heavily emphasizes one part of the causes over the other (also the French revolution is a much worse venue for "vibes" than today)
no he explicitly negated "not material conditions" - verbatim quote - it just to be obnoxious and beg for negative attention so he could cry about how mistreated he is by the subjects of his impotent violent revenge fantasies.
whatever explanatory or predictive powers historical materialism has - you'd have to read the source texts in the first place to discover to what extent - its analytical utility is infinitely moreso than billy's infantile vibes based philosophy he made up online to troll the left with