It's not just that there's only two Christmases. It's that Christmas fell on Sunday in 2022 and Monday in 2023, and the article already established the attacker

It's not just that there's only two Christmases. It's that Christmas fell on Sunday in 2022 and Monday in 2023, and the article already established the attacker mainly worked Tuesday-Friday. The note about the attacker never working on New Year has the same problem (New Year's Eve/Day always lines up with Christmas Eve/Day, so would not have hit the Thu-Fri window either).