Just read through all the comments, I think with regards to the original mini posted, it IS crossing a line, in the same way as having a photo on the wall of a concentration camp gas chamber in use during WW2 would be. Really can't see why anybody would actually consider this mini as appropriate to a) sculpt or b) buy - it's not artistic, would have very limited uses in a game and certainly isn't fiction of any kind. As has been pointed out, it's not sculpted or painted to a particularly great standard either.
Mini's that 100% represent real life are not always to everyone's tastes, however I think when the subject matter is something that is "morally inappropriate" it most certainly has crossed the line.