Agree. I am a second-generation Italian-American. All of my mother's and father's siblings were Democrats. All of my five brothers and sisters are Republicans. It doesn't take long folks. Unless you assume the brainwashed will either stay that way forever (some groups do) or are just stupid (most aren't).
This is the distinction that Sam Huntington draws between the illegal flood of people from Mexico and immigrants from earlier generations: There is no reason for illegals from Mexico to assimilate (and eventually vote Republican, for our purposes) because (i) we share a huge border with their home country to which they can come and go from whenever they like, (ii) the elites insist that multi-culturalism trumps any sort of American creed or identity, (iii) many simply come here to exploit the resources of the US without concern for the country itself, and (iv) the elites of the Mexican community see a future in which American becomes heavily latinized and want nothing to stand in the way.
Your Italian grandparents and family had no option, if they wanted to stay here and prosper, but to assimilate. That's no longer true.