For the sake of truth in advertising, I kept looking for an image of brothers going at each other, fighting tooth and nail. All I could find were horribly saccharine, the one above being the less mawkish of the bunch.
My take… the greeting card industry is at it, again.
However, it does have a touching back story. Read about it here: National Siblings Day
And so it goes.
I had not heard of this “Special Day” until now. I would agree that this smells like another Hallmark Holiday.