This kind of problem is also showing up on Quora. Some of the answers I've spotted are so obviously wrong that you can tell a person didn't write them.
So many people were clicking on the link from here that it inadvertently DDOS-ed my server. I had to turn on the "under attack" feature in Cloudflare just to get the other sites running again.
The convention site in question had a GA tag, and it was in search console, and I had submitted a sitemap. Search Console knee the site had 9 pages in the sitemap, and had only indexed the homepage.
The other pages weren't rejected, declined or 404ed - they were simply ignored.
Yep. Amazon, Kobo, Apple, and Google (55% of the ebook market) all have operations in Germany. They cannot pull out, and nor can the local sellers that account for 40% of the ebook market.