Why is the extraction of copper from pyrites more difficult than that from its oxide ore through reduction?

(N/A) The Gibbs free energy of formation $\Delta_r G$ of $Cu_2S$ is less negative than that of $H_2S$ and $CS_2$.
Therefore,$H_2$ and $C$ cannot reduce $Cu_2S$ to $Cu$.
On the other hand,the Gibbs free energy of formation of $Cu_2O$ is greater than that of $CO$. Hence,$C$ can reduce $Cu_2O$ to $Cu$.
$C_{(s)} + Cu_2O_{(s)} \longrightarrow 2Cu_{(s)} + CO_{(g)}$
Thus,the extraction of copper from its pyrite ore is more difficult than from its oxide ore through reduction.