Most countries have something closer to a civil law as opposed to common law basic system; and most of the ones that have a common law system also have parliamentary sovereignty as part of their Constitutional order, whether or not they have an actual written Constitution; this doesn't really change the basic subjectivity of legal decisionmaking, but the combination of a common law tradition which frames interpretation of the Constitution and the absence of parliamentary sovereignty gives the US Supreme Court more scope than most high courts have to start with, and more scope naturally means more room for subjectivity to manifest.
Germany's constitutional court also does so from time to time, unfortunately.
Decades ago they invented a right to "informational self-determination" that has no textual basis in the constitution.
It's a good right to have. I understand why they felt compelled to do so.
But every time the court decides something like this they have to demarcate the borders, where it applies and where not. In doing so so they draw red lines that the political process can hardly overcome, even if it might have yielded a better end result by giving the edges a little different form.
Last year our court invented a right to school education, again without textual basis.
In my opinion, the degree to which judging is subjective and ideological is overstated in order to support a level of judicial interventionism on the part of the U.S. Supreme Court that is quite unusual in developed countries. Go read German or Dutch high court opinions--they are a lot drier!