Garen yelling "DEMACIA!" when killing an enemy Darius?

This is something I've noticed myself, but when I brought it up anywhere else, they call me a liar. Try it yourself, really.

Pick Garen, and hope that your opponent picks Darius.

Then have Garen kill Darius. Hopefully, he's not casting Courage at any moment.

Right after scoring the kill, if you have your camera on Garen, you will hear him yelling "DEMACIA!!" just like if he casts Courage (or part of the Spin2Win meme).

So, Riot, is this a bug or it's purposefully put there to emphasis a rivalry? I guess Darius couldn't counter with yelling "NOXUS!!" if he's the one scoring the kill instead.

Well, Riot, can you confirm this? Or you confirm that I am a liar?