There's a very old axiom that there are only seven great concepts (or ideas) in literature and all works of literature are merely recycled versions of those ideas. The same thing applies to this thread. The ideas generated of pigmy-sized humans with blowguns can be traced back generations. It is a staple of pulp fiction and from African folklore. The fact that something cropping up in game terms that is based upon this shouldn't really surprise anyone. After all, how many times have we seen a "rescue the princess (substitute any important figure) from the dragon (substitute evil nemesis figure) and prevent the end of the world" story through the years? If you apply the same accusations of theft/lack of originality, then half of the D&D modules published would fall under the same argument.
Writers derive their inspiration from other sources. We draw ideas from other books, movies, news, and real-life. Case in point, when writing Egyptian Gods for Bastion Press, I created a Moon Knight prestige class that is a homage to the original Marvel Comics character done in the late 70s-early 80's. If you are familiar with the character and you read the prestige class, you will see the similarities. Does this mean it rips off Marvel? Not hardly. It is far from a direct copy, but rather one professional's way of acknowledging the genius of another's. You see this all of the time, especially in the movies. Anyone care to count all of the little tip-of-the-hat homages that were present in Phantom Menace or even Monsters, Inc.? Just because similarities exist doesn't mean it is an intentional attempt to blatantly rip off another's idea. Sometimes it is just someone's way of tipping their hat...