This thread has kind of dumped on Italians a bit but tbh, the few experiences I've had with the ones from Italy were great and I've even known some legit cool ones from west coast states and such. Now what OP might have been on about are the particular East Coast types from Long Island and such who are middle class, suburban, and tend to fit a certain archetype. New money rich, plastic culture, arrogant rude women, combative men looking for trouble, sleazy dudes who you cannot trust around women (like legitimate borderline rapists), and pent up anger like none other.
Now I am all too familiar with the type, the arrogant stuck up women and yeah, men who are some massive psychopaths. It all comes down to the fact that these guys were not viewed in the same light as the WASPs or even the Irish many decades ago. Now while that kind of racism sort of died down and turned more towards everyone hating minorities and Muslims, the inferiority complex is still kind of there.
A lot of the women prefer the blond haired Conor McGregor or Machine Gun Kelly (rapper) lookalike badboy if they are looking for a fling and the Tom Brady or Chris Hemsworth type of clean cut dude for an LTR, even over their own men. The men themselves know this deep down so they get really sour and overcompensate by being more douchey, aggressive, loud, combative, predatory, and yeah even racist. This is exclusively a Long Island/Jersey thing, even Italians in Brooklyn and Queens are chill.
The only reason it is really bad with Italians is because the culture values image, perception, and social ladder climbing so they overcompensate more. TBH though, the women and people in those areas kinda suck, they are the butt of a lot of jokes. The true elite of NYC tend to grow up in Manhattan itself or in Connecticut/New England states, often they are Jewish or WASP.
Deep down, the people in Long Island and other areas know it, hence why they tend to be extra douchey, rude, combative, malicious, narcissistic and yeah even racist.