Laws differ a lot among different countries, and especially so when it
comes to negligence. And I have no idea of the Canadian law. That said:

Is Fuel Exhaustion A Criminal Act?

No. But the question is completely wrong.

A Canadian court has found an Alberta pilot guilty of criminal
negligence and unsafe operation of an aircraft for a 2002 accident
that led to the death of a Kansas man. Mark Tayfel admitted he
misjudged the amount of fuel required for the round trip from

So he run out of fuel by negligence. Negligence in itself is no criminal
act. Had he just run out of fuel and forced landed somewhere, well, so
had he, end of story. Had he killed or injured himself in the process,
again, so he had, and end of story. (Maybe not in regard of insurances,
but that's a different question.)

But: He killed someone else in the process. And as different as
legislations in different countries are, most of them see killing
somebody by negligence as a criminal act.

So the answer to your question is: No, running out of fuel is no
criminal act. But killing somebody by negligence is. And the negligence
may be the fact that you miscalculated your fuel need and consequently
run out of fuel. BTW, not requesting a priority landing when you know
that you're short of fuel may also be negligence and so on.