>It must be a pretty hard problem.

Not particularly. The only hurdle is the database. I collected all the Seeking Alpha articles and tags very easily before organizing the data and building the model to astonishing success on Colab.

An alternative would be to find literature from great writers (James Joyce, Emile Bronte, etc.) and divide it into paragraphs as texts, remove paragraphs that are too small and tag those paragraphs as a 1 and take awful writing (Twilight, Ann Coulter, Mein Kampf, etc.) and do the same with them tagged as 0 before training the model to separate the two.