Private property is bad. Rent and interest are stolen from workers. Capitalists are all greedy, grasping, mean, and exploitative. By extension, wealth is considered ill- gotten and tainted. We need only document real cases of nasty capitalists and exploited workers, ignoring everything else, to make the case seem valid.
Totalitarianism always requires a permanent enemy, a group to hate.
It is little remembered now, but Marx first advertised his theories are more economically efficient. Only when they lost the argument against efficiency did Marx and the communists turn to a moral argument, saying that capitalism was unjust. Only then did they prevail, for there was no rebuttal in moral terms. Whereas socialism and communism appeal to hatred and envy, capitalism not only appeals to our moral instinct to help others, but harnesses our energies to that purpose and rewards most those who do the most for humanity. All of us, you see, live in a whirl of activity that involves the transfer of goods and services.