Labels are not entirely BS. Sometimes people do have definite ideological beliefs -- by this I mean a person just doesn't go down a list of policies and checks "yes" and "no", but actually have an underlying theory about the purposes and functions about society and base their decisions on this -- and will themselves accept a label themselves.
I do agree with your point that often there is no real meaning to the word "consrvative" or "liberal" other than a derogatory label to pin on your opponent. But that is why I asked this question in the other thread (my flippant answer here notwithstanding) -- to try to get people to think about what these words mean when they apply them.
As I've stated before, is seems that a lot of political discourse is just shouting slogans without really thinking about what, if anything, your slogan means. On the other hand, if we are really going to try to discuss social problems I think it does help to categorize the suggested solutions so as to try to figure out what the underlying assumptions are and to evaluate them.