“I like being responsible with money” is a pretty anodyne and meaningless sentiment in itself. Everybody thinks they’re responsible with money! But responsibility depends on the underlying value judgment of the thing being bought. Claiming “fiscal conservative” is a way to push that value judgment while pretending it’s just a bookkeeping exercise.
Relatedly, “social liberal” is not a distinct dimension of liberality. It’s always deployed as an ambiguously positive moral valence to offset the ambiguous negative valence of “social conservative.” In this way you can see that “social liberal/fiscal conservative” is not an actual ethos, it’s evasion and deflection rolled into one.
It’s immaterial. You don’t need to be part of a power structure to be invested in it. Lots of people who aren’t white or men can benefit from helping white men stay in power. Ask Clarence Thomas. More depressingly, lots of people believe they stand to benefit from the white male power structure. Ask any self-described southern white person who thinks the immigrants are taking all the good jobs.