Even if similar markings are not required by law everywhere in the USA, food manufacturers are probably afraid of getting sued due to violating local laws, or even international laws if the food is transported across borders, so it’s probably negligent to neglect printing them.
I don’t know about today, but in the past New Jersey required that “expiration dates” be stamped on bottled water: https://nj1015.com/does-bottled-water-expire-nj-was-the-only-state-that-thought-so/
Even if similar markings are not required by law everywhere in the USA, food manufacturers are probably afraid of getting sued due to violating local laws, or even international laws if the food is transported across borders, so it’s probably negligent to neglect printing them.