In my opinion, this case was important at the time it was decided (1989) because it helped to get what we now call the "culture wars" started.
When I use the term "culture wars" I am referring to the apparently deep splits between relatively liberal, urban, coastal America and more traditional "heartland" America. We now see these "wars" being played out over issues like gay marriage, abortion and other, typically religious or patriotic, issues.
At the time that the case was decided, these "wars" were not really in full swing yet. But this case helped get them going because it was so clearly opposed to traditional values of patriotism. It therefore angered many people and helped to fuel the perception of a major gap in values.