can a weapon intend harm? can a company who creates weapons intend harm? what if the companies factory explodes due to a mishap and takes out a few city blocks, is the company held liable because they (and the weapon) didn't intend harm?
Yes, but, generally, in the United States, they would be liable because their negligence caused the harm (giving rise to civil liability), even if they did not intend to cause harm (where having such intent would have given rise to criminal liability).
And I say "generally" because there can be instances of criminal negligence, but that varies from jurisdiction to jurisdiction as well as the underlying facts.