IIRC, when PO Ackley did his famous experiments trying to blow up rifles, the Carcano was one he could not blow up. They are fair rifles, and serviceable. They were designed and fielded at a time when bayonet charges were still a very real part of military life, and the design endured about 50 years, so they could not have been all that bad to begin with. I don't know about the 8X57 Carcanos being unsafe, but I can guess that a WW2-era Carcano carbine in 8X57 will rattle your filings.
Never try to educate someone who resists knowledge at all costs.
But what do I know?