The argument was made that the kneeling was for a fallen soldier. I don’t think that interpretation is correct. You, too, seem to agree that that’s not the only reason to kneel for the cross.
Edit: Upon a bit more reflection, this particular graphic for this saying could mean a dead soldier since it’s a soldier praying. And crosses are sometimes used for soldiers’ grave markers. But not always. And you can find soldiers praying in front of other crosses. And soldiers don’t pray only for the dead when kneeling before a cross. I’d have to ask the artist her intentions.