Use whatever fits your needs, just because it didn't fit your needs doesn't mean you should go forcing your opinion upon others. Many people including myself have had nothing but great experiences using NGINX and I don't actually see any real argument here to stop using NGINX.
Based on the tone of the article I get the kind of vibe that the author has the "I liked this band before they became mainstream" mentality about software. NGINX deserves all of the money they can get, they have a great product that is worth paying for and it's quite usuable without paying a cent, so I don't understand what there is to complain about.