Sure, there are always complex psychological reasons why people do things. What I'm talking about is the blasphemer's articulated explanation:
Is it really that hard to imagine that the interrogator, the Nazi, or the cemetery-destroying kids might respond as follows if asked "why did you desecrate _____?"
"Why not?" or "Because I can" or "Who cares why?" or "I dunno" or "Why does it matter?"
If the answer is one of these or something similar, then that is desecration of the sacred for desecration's sake.
In fact, Stanley Fish's argument about the Mohamed cartoons is that some articulated, ostensibly political reasons (e.g. "free speech!") are really just fancy ways of saying the same types of things as above: The cartoons were published for no other reason than that the editors _could_ publish them.
So I think plenty of real world examples will fall into my definition of blasphemy. If the definition needs to be footnoted to add this clarification, then that's fine too.
-WD