Like the OP stated, why would someone do this? And if you're going to make a fake why write in French and not German? And there's nothing that weird about someone making a dyslexic mistake on a spelling. If you are afflicted with this, as I have been for years... you would not find it so abnormal. It's not an impossibility anyway. Once having made the mistake switching the E for the I, there would be no fixing it, just merely going on with the word misspelled...
In French it reads roughly "in memory of my naval military service" which isn't all that weird if someone was making themselves a memento. Again, almost too bizarre to be an obvious fake. And again, I don't think it's an impossibility.
Poor engraving? It's done with an electric pencil, looks about normal for this kind of engraving. In fact, it's quite good.
A comment about "the Kriegsmarine being nothing to be proud of by 1944" is really bordering on the ludicrous... The beginning service date is 1940, which was in the heyday of the German war, especially on the high seas. But regardless of this, and IF this item were to be genuine I'm not taking into consideration here... but the premise that someone wouldn't be proud of their service is preposterous.
I certainly wouldn't dismiss it as a fake offhand, but I would be very interested to know what the prop is from, and is it period?
There is no way for anyone to really know for sure, and there are certain details about it that in fact point in the way of not being a fake, for me anyway.
I think one plausible explanation for the French would be a French born person of German descent (or Alsacian) having enlisted in the Kriegsmarine after the fall of France, the 1940 enlistment date would fit. Otherwise the Germans do have a history of using French in decorations, "Pour Le Merite" being the most obvious one to come to mind.
All pure conjecture, really.