I was hoping the author would advise against using this, because after doing this your website isn’t accessible.

I don’t think this is the answer to web scrapers, since it so adversely affects people with disabilities. The web is one of the few things that is structurally (reasonably) accessible by default even if making inaccessible websites (like the author’s is now) is possible.

If you have to choose between accessibility or letting scrapers to access your site and scrapping accessibility, you should choose accessibility.