The red herring

AKA biased sample
AKA ignoratio elenchi
AKA irrelevant conclusion
AKA ignoring the issues
AKA ignorance of refutation

The red herring fallacy is where an argument is made using irrelevant terms that don’t have any bearing on the point being argued.

Wikipedia entry on the red herring fallacy

There's probably no god.  Now stop worrying and enjoy your life.