The article is just not very good. You might like Emily Riehl's article in Scientific American last year: https://www.scientificamerican.com/article/infinity-

The article is just not very good. You might like Emily Riehl's article in Scientific American last year: https://www.scientificamerican.com/article/infinity-category-theory-offers-a-birds-eye-view-of-mathematics1/ https://www.scientificamerican.com/article/infinity-category...