Not sure this is political correctness?
I have used the term 'Jew' like you, but I was always hesitant precisely because of the point Foof brought up..It can be used as a slandering word.
I suppose 'Italian' and 'English' could be as well, but I've never seen this; I think for these words to be considered a slander they would have to be spoken with emphasis or if written, italicized and in the proper written context!
So, I don't think 'Italian' carries with it near the weight of 'Jew'. I conceive of a hierarchy of potentially disparaging words that can be misconstrued, especially among people that don't know each other and especially on the internet (see the former point!).
This same argument was used over the fighting Irish logo over the Redskins logo. False equivalences. (at least today, one could have made an argument that at one time it was bigoted as the Irish here were seen in a less than stellar light at one time in the states history - still the Irish weren't slaughtered and pillaged from either).
Hiding behind not wanting to be politically correct is no excuse for bad manners.
On a similar note, in England (and I think the rest of the world) we grew up calling Asians, Orientals. Not a bad word anywhere but here. Found out quick..