It's not mindless.
The movie acts as a metaphor for America’s descent into moral ambiguity following the terrorist attacks of 9/11. The hunt for John Harrison is analagous to the search for Bin Laden and the debate about whether to launch photon torpedoes at the Klingon home world is relevant to current debates regarding the morality of drone strikes.
It's also quite fun.
For more information on why the film is actually surprisingly political:
And yeh, which of the TNG films was a cutting social commentary with interesting things to say?