Yes they are. The precedent was set in the 1800s with rulings on slavery. Since then the SCOTUS has made rulings that shape the country. They interpret the laws and their application, which in turn shapes the US.
There is absolutely nothing about having 9 people with lifetime appointments given power to "shape" the country that should make you comfortable. If that idea doesn't scare you then either you aren't thinking it through very well or you've got a wildly different definition of "shape" than I do in this context. The phrase "Legislating from the bench." should pretty much always have a negative connotation.
The fact you couldn't even make it through your original assertion without politicizing the Court's purview (liberal=progress) is telling.