Article is full of bs.

Democrats were the pro-slavery party; the Republicans were abolitionists. After slavery was outlawed Republicans went to bankers and Democrats could not win Presidential elections. While they went Jim Crow in the South, they courted immigrants and laborers in the North, as unions were forming. Unions became the single biggest category of donors to Democrats. Meanwhile, wealthy individuals and business owners, as a general rule, supported Republicans.

Democrats have not been losing the labor vote because more people are graduating college. Democrats have been losing the labor vote because New Democrats sought out the same sources of money as had been funding Republicans. Consequently, both are now funded primarily by big businesses, banksters/Wall Street and wealthy individuals.

As has been known since Biblical times, no one can serve two masters. Democrats chose the wealthier set of donors. So the former donation-based love affair between union leadership and Democrats got more and more one-sided. https://www.thenation.com/article/archive/afls-trumka-pols-selling-out-workers-ive-had-snootful-st/ And more and more of the rank and file became disenchanted with Democrats for various reasons, perhaps starting with police in New York. https://www.wnyc.org/story/john-lindsays-civilian-review-board/

In any event, no President who breaks strikes can be considered the most pro-union President. Moreover, as the UAW was contemplating this strike, Biden was contemplating bailing out suppliers, which would have lessened the impact of this strike, which was already problematic.

After I read what a pro-labor POTUS Biden supposedly is, I could read no further.