There is some truth to this article. You can automate factories and produce more (& better quality) with fewer people. However, I also thought they changed the definition of manufacturing at some point, to include food service workers.
Turning raw crude oil into refined gasoline is also manufacturing. Refinery jobs are usually good paying, non union jobs, so naturally the Dems want to destroy them. A common excuse for opposing the Canada Pipeline is that it would only bring oil to southern (non union) refineries who would then sell the refined gasoline to China. Even if true, wouldn’t that increase both manufacturing and exports?