I don't think you can hand wave away all risks like that. Negligence is a thing and a waiver won't protect you from it.
Of course, there's the question of if the candy-murder factory was negligent. I'm sure oompa loompa lawyers will be arguing in court for many months.
Are you suggesting that because the charges were dropped, he's not a murderer? Because that's not how language works. Being legally proven to have done a crime is not the same as having done the crime. You can be convicted while innocent or have charges dropped when actually guilty. It's perfectly valid to call someone a murder even if the legal system is a failure.