Marxism was one thing envisioned by Marx.
But time has passed, & the definition of "marxism"
has evolved over a couple centuries from its
original arcane theoretical construct.
Consider a representative common definition....
Definition of Marxism | Dictionary.com
the system of economic and political thought developed by Karl
Marx, along with Friedrich Engels, especially the doctrine that the state throughout history has been a device for the exploitation of the masses by a dominant class, that class struggle has been the main agency of historical change, and that the capitalist system, containing from the first the seeds of its own decay, will inevitably, after the period of the dictatorship of the proletariat, be superseded by a socialist order and a classless society.
Set aside the possibility of some claims, eg, there'd ever
be a classless society. A "socialist order" requires a
government in order to prevent non-socialist voluntary
associations, ie, capitalism. Is it possible to reconcile
statelessness with socialism? No. As we see, the more
socialist a country, the more authoritarian it is, eg, PRC,
USSR, Cuba, Khmer Rouge.
So when the OP refers to "marxism" its fans here create
2 problems in their objections....
1) Marxism is more than their extremely focused 19th
century definition.
2) The OP speaks of "drift into", which is about movement
in the direction of marxism....not
being marxist. This allows
tending towards some, but not all characteristics.