Sure Papua New Guinea scores 5/5 on the "Violent Crime" assessment (to the US's 2/5), but the US incarceration rate is 5/5, while Papua New Guinea only scores 1.5/5.

The US also has much more weapons exports, and external military involvement.

People deciding where to travel are largely thinking about "violent crime" levels moreso than "how many fighter jets does this country sell"

This report tries to also take into account things like "Military size, expenditure, and weapon exports", which surely indicates a non-peaceful nation, even if on the ground citizens can live peacefully.

If the definition of "peace" includes nation-level involvement in conflict, then I think it's very fair to argue that the US isn't a peaceful country. Papua New Guinea is not providing significant military support to multiple wars at once. The US certainly is.