Well a stalinist would not be a impartial SCOTUS judge about taxes and the human right of property and other more civic democratic human rights.
In Germany you still can't become a public servant, if you are openly a communist or nazi.
Why should you become the highest judge then, if you are a catholic religious zealot and the next important cases in the next years will be about abortion laws from some federal states?
Even worse is that Barrett was quiet in the public hearing about her firm anti-abortion stance since 2006.