Hand-written HTML may have had the occasional error but when tools (remember FrontPage and Dreamweaver?) started to be used their output was dramatically worse. This was certainly not controversial at the time. Nowadays with templating languages and frontend frameworks (React is operating on the DOM but it is still just HTML elements in the end) there's still a human picking the elements and attributes that are rendered, even if there is a layer of indirection. So I don't really get the argument that hand-written HTML is bad, especially since it's ubiquitous. HTML was designed with hand-authoring in mind.