Of course there is a sense of isolation when no one around us understands the meaning of what we say. Namely, the meaning which what we say has for us. But this does not mean that communication is impossible and we are left all alone on our shore.
Oskar Maria Graf uses a much more suitable allegory to explain these feelings of separateness. He describes humans as being prisioners. We are prisioners of ourselves. Prisioners of our educaion, our parents worldview, our own experiences, our believes. Our Shadow keeps us imprisioned. Our past and its imprint in our unconscious makes us see the world in a unique way, but it also is a hindrance to understand each other, because we tend to ignore the fact that everyone carries his baggage of past experiences around.
I have also to vehemently disagree with the pluralist and extreme social constructivist views that the world is not there as such, but it's all a matter of our own imagination and negotiations. All science would be completely nonsense and we would have to abandon any pursuit of knowledge if there was no objective world as such.