Marxism isn't the alpha and omega of socialism.
Marx argued for a socialism based on class.
Mussolini argued for a socialism based on nationalism.
Hitler argued for a socialism based on racism.
The various flavors of socialism necessarily subject the individual to the aims of the state (whether those aims are described as for the class, nation, or race) and are on the opposite end of the spectrum from a economic order based on individual property rights and freedom of exchange in accordance with their own desires - capitalism requires liberty.
"It is thus necessary that the individual should come to realize that his own ego is of no importance in comparison with the existence of his nation; that the position of the individual ego is conditioned solely by the interests of the nation as a whole ... that above all the unity of a nation's spirit and will are worth far more than the freedom of the spirit and will of an individual. .... This state of mind, which subordinates the interests of the ego to the conservation of the community, is really the first premise for every truly human culture .... we understand only the individual's capacity to make sacrifices for the community, for his fellow man."
-Adolph Hitler, 1933
