War!

Perhaps the wrong phrasing. Maybe they meant it was the first to actually treat it as a war. New hope had uncle o and aunt b killed, but off screen in the theatrical release, and some throw away jawa and sand people casualties- but by and large the characters were shown largely uneffected by the losses. Jedi had some grieving ewoks and such- but Rogue One was the first to alnowlege there was a really dark and personal toll to war, and really show it as more than an adventure where main heroes were safe and it's all good against evil. We all have seen the memes and musings about all the people killed on the Death Stars, that's without taking alderan or other battles into account either. Such massive loss of life without even a nod from the film or retrospection by the characters. They just need to defeat the "bad guys" and then everything will be happy, maybe a montage of ghosts of beloved characters to show the "sacrifice of war" in which the central protagonists killed thoisands.

I was fairly certain the Phantom Menace most certainly had war in it.

unpopular opinion but i actually like the new star wars movies fam changing up the plot and the typical good guy survives or the bad boss like bad guy.