“Hyphenated-Americans” were literally a Communist plot. Stalin’s post-WWII plan was to destabilize the United States by sowing Balkanization among our different races and ethnicities:

Great Moments in Leftist History

Quoting from School of Darkness, the autobiography of Communist-turned-ex-Communist Bella Dodd:

By April 1945, there was evidence of trouble in the Communist Party. Uneasiness increased among its functionaries. I first became aware of this in my work with the Italian Commission of the American Communist Party.

One day two foreigners appeared in our midst, recently come from Italy. Berti and Donnini were a smooth, attractive pair, who called themselves professors and had become leaders of the Italian Commission. They immediately started a controversy, about the work among national minorities.

Earl Browder at the convention of 1944 had insisted on the elimination of a sense of difference among the foreign-born and had moved to have them treated as part of the American labor movement. To this Professors Berti and Donnini offered strenuous objections. They emphasized the importance of separate national organizations, of encouraging the foreign-born to use their languages, and of circulating foreign-language newspapers. They encouraged the organizing of the different national groups almost as if these were foreign colonies. It would strengthen the sense of nationalism among them, they asserted, a necessary thing for the building of world communism.

These two Party functionaries found themselves on the carpet for their unwelcome views. Plans were on foot to expel them. Then, suddenly, came the amazing news that they were members of the Italian Communist Party! Up to this point, like others, I had regarded them as honest but misguided foreigners with a penchant for disputation.

Now I realized that nothing they said had been unpremeditated, and that they were not speaking for themselves. They represented the International Communist movement and it was clear that Browder’s approach to the national problem was in disfavor with some sections of world communism.