I don't really use it (as far as I know) but I had never really thought about how inappropriate it was. I think it comes from the Seinfeld episode with the 'soup-nazi' - it just kind of caught on from there and I know lots of people who say it in relation to lots of things. When I think about it, I can totally see that it is offensive, but it is amazing that it is so normalised that I don't really bat an eyelid when I hear it.

Thanks for your post Onyx