I get your point and agree the loader is complicit, but must respectfully disagree he killed her...
The person of Alec Baldwin, who failed to determine the condition of the firearm, held it in his hand, pointed it at another person and pressed the trigger is the one responsible...
Observing the rules for safe gun handling along with Mr. Baldwin NOT being an arrogant prick would have prevented her needless death...
Indeed, involuntary manslaughter at the least.