Say what you want about how it embodies 'nationalism,' it is every bit as stirring a song as the Marseillaise, and a hell of a lot less overtly warlike than that song. Which is not at all surprising, since the words were written by a German republican in exile for his ideals.
Come to think of it, it's even less warlike than our own National Anthem, which includes the following lines:
Oh where is the band that so vauntingly swore,
Through the tumult of war and the battle's confusion,
A home and a country would leave us no more?
Their blood has washed out their foul footsteps' pollution.