Not the first time ever. Probably not even the first since Mo’s boys took over 1400+ years ago. Brits occupied Iraq during WWII and probably allowed it then.
Iraqi Christians were allowed to celebrate Christmas throughout much of Iraq’s history up until the modern day. Same way the Jewish community was dhimmi-tolerated until after the founding of Israel when it became a political issue.
To pretend that the present is the same as the past is to ignore the rapid acceleration of Islamic hostility in modern times.