The headline is not apt, the piece is not really making a strong case "against" Chopin. There is a slight attempt to build up some illusion that Chopin was once not held in high esteem. Well, that is a very weak argument indeed, as he was a child prodigy touring Europe in his teenage years, and then subsequently was very well known to the other famous romantic composers, most of whom thought he was a true genius of melody, finesse, and a master of chromaticism and narrative piano writing. Look no farther than Liszt's storied relationship with Chopin, they played together at salons and gatherings, they played each others works. Similarly, the Schumanns loved Chopin's work. He achieved a very high fee for teaching as well, there were numerous very wealthy Parisians eager to have training with him. Furthermore, there was and is a very, VERY strong tradition of classical pianists playing his works. Consider Debussy's performance of the fourth ballade at his conservatory, when it was stated he performed it as if "without hammers". So, no, there is no case against Chopin's mastery, this headline is click-bait.

The linked article is really a pseudo-book review of the recent biography "Fryderyk Chopin: A Life and Times" by Alan Walker.