Republicans used to care about income equality. You can tell from this long-lost article by then Senator Rick Santorum:
“Despite a strong economy through the 1990s, the gap between the rich and the poor expanded. Among Americans who reach age seventy, the top ten percent own more wealth than the bottom ninety percent. How do we address this inequity? […]
Initiatives that encourage individual wealth creation are imperative to closing the gap between the rich and the poor. I believe the government can play a role in helping many Americans who struggle to enter the economic mainstream.”