I swear I don't mean this in a snarky way: I don't quite understand how, functionally, interpreting the law is all that different from creating it. Deciding to interpret a law one way or the other (because of the ambiguity of language and intent behind laws) has impacts on people's lives, the freedoms they have, what rules they are subject to, etc.
People argue this point a lot. As an example, Miranda rights are an affirmative requirement - that is legislating from the bench, but people like it so don't complain.
I'd highly recommend a podcast called 'Five Four' where they talk about the supreme court as a political body, rather than as the impartial "balls and strikes" role that if purports to be.
Their job is to apply the Constitution, and in this case the Constitutional principle is quite clear (so clear that it led to a 9-0 decision). Specifically, the "takings clause" of the Fifth Amendment: "... nor shall private property be taken for public use, without just compensation."
