I’m with Squawk. If we apply the Reason model of accident causation, then the presence of Ice is one of the
‘holes” in the cheese that lined up that day.
.....And since it is an illegal drug with known ill effects, that the pilot chose to consume of his own free will, then it is the cause.
We see meth users on freeways occasionally, they are the ones travelling 30-40kmh faster than everyone else..until they crash.