I was hoping the author would advise against using this, because afterwards 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 are structurally (reasonably) accessible by default even if making inaccessible websites (like the author’s now) one is possible.

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