Is it your contention that political journalism should refrain from diagnosing powerful trends in American (and European, for that matter) politics? The intersection of demographic factors is historically unique & plainly visible in the data.
A page of history is worth a volume of theory, e.g., https://www.washingtonpost.com/news/monkey-cage/wp/2014/12/16/when-party-machines-turned-immigrants-into-citizens-and-voters/ … https://www.nytimes.com/2014/01/18/opinion/the-forgotten-virtues-of-tammany-hall.html … https://prospect.org/article/riddle-immigrant-voting … The data on assimilation trends is pretty extensive. Sean Trende's book had