The former were all about a minority controlling the majority, while the latter is about the majority being in control (although that does not work out all that well always either).
Note that the it is almost impossible to discuss this due to overloaded terms like liberalism which means the opposite depending on who you ask. I define leftism like this: https://en.wikipedia.org/wiki/Left-wing_politics
It's just that I've never seen it in (historical) contexts outside of describing the pre 1920s revolutionaries.
They used "bolshevik" as a term of endearment especially in reference to the old party members.
don't worry most of the left repackaged the old communism into moral relativism and is no longer trying to win that unwinnable battle to keep communism as an ideology detached from all communist implementations.
it's mostly the older guards that still try that line.