Hi.
Has nothing to do with the word "mother" in English. You could perhaps say that it "gave birth to..." but what it actually means in this context is that the specific operation discussed was later referred to when similar operations were planned and carried out and in this respect it was their "parent".

Saying "the mother of all" as far as I know means referring to something as the best or worst of it's kind (as in "mother of all screwups") and this is not the case, the point here isn't that it was best or worst but that it was one of the first of its kind and inspired later similar missions.

Hope this helps.