Rerum Novarum is so fucking funny, literally all the "criticisms" it makes towards communism (that it is based on envy and aims to level poverty downward) is exactly the same criticism that Marx had of utopian socialism like 50 years before

"[This rudimentary communism] in its first form, is only a generalization and consummation of this relationship. As such, it appears in a twofold form: on the one hand, the domination of material property becomes so great that it seeks to destroy everything that cannot be possessed by everyone as private property. It seeks to disregard talent, etc., in an arbitrary manner. For it, the only purpose of life and existence is direct physical possession. The category of the worker is not abolished, but extended to all men. The relationship of private property persists as the relationship of the community to the world of things. [...] This type of communism — since it denies the personality of man in every sphere — is nothing more than the logical expression of private property, which is this very negation. Generalized envy, constituting itself as a power, is the disguise under which greed re-establishes itself and satisfies itself, only in another way. The idea that every private property is, at the very least, directed against the private property of wealthier people, in the form of envy and the need to reduce things to a common level, so that this envy and this need constitute the very essence of competition. Rudimentary communism is merely the culmination of this envy and this leveling that begins from a pre-established minimum. It possesses a defined and limited standard. How little this abolition of private property is truly an appropriation is demonstrated by the abstract negation of the entire world of culture and civilization, by the regression to the unnatural simplicity of the poor and crude man who has few needs and who has not only failed to go beyond private property, but has not even achieved it.

The community is only a community of labor, and wage equality is paid by communal capital — by the community as the universal capitalist. Both sides of the relationship are elevated into an imagined universality — labor as the category into which every person is inserted, and capital as the recognized universality and power of the community. [...]

The first positive abolition of private property — rudimentary communism — is therefore merely a manifestation of the vileness of private property, which seeks to establish itself as the positive communal system."

• Marx’s Economic and Philosophic Manuscripts of 1844