It's long been E-Bay Auctions policy to not allow the posting of auctions for firearms or live ammunition of any type. I can almost agree with their position, since with the plethora of laws pertaining to such sales just in the US, much less the world, would make it an almost impossible task to remain legal in every area where they operate, and they don't need the headaches.
Having said that, E-bay has gone overboard in the other direction in their effort to protect themselves to the point of absurdity. and in a classic case of demonstrating absurdity by being absurd, an E-bay seller in Australia has put up this "auction". And you don't see the humor in it, I truly feel sorry for you.
He also put up another little visual to further make his point:
E-bay really does need to lighten up on the PC/GFW bit a little bit. I don't think that they need to sell weapons, but to disallow even the slightest referance to them to pull an aution as breaking the rules is, to put it mildly, ludicrous.