THAT is a truism, and there is another.
Capitalists create communists through capitalism's ruthless exploitation of those without capital.
AND, labor unions were created as a response to capitalists. Again, a response to ruthless exploitation, which is the name of capitalism. No one wants to be in a labor union, but want even less to trust the tender mercies of capitalists.
And capitalism is setting itself for another fall, sort of like the French before their Revolution.