Yet, the original comment was sensible just because of two things:
1. Everyone on the Internet that uses a search engine knows what a good or bad one is. It has one purpose: turn your query into information you can use. If people say it doesn't or it's "shitty," then it's not doing it's job as a search engine effectively. All we really need to know.
2. The more specific information is better directed at the DuckDuckGo support or development teams to help them improve their alogrithms. Posting piles of data in Hacker News comments would only seem useful for the use-case I described above, people studying effectiveness of search engines via terms + results (better done elsewhere), or people reverse engineering DuckDuckGo's algorithm. I don't see why we'd expect people to produce or post that data as it's a lot of work and screen space.
2) There is at least one ddg developer here (not me), and HN is generally a good source of constructive feedback for startups. Maybe the original commenter's query string would help ddg or a competitor improve their product.
I am sure there is a presentation bias. I am sure that there are plenty of cases where a user cannot tell if a set of results are good or bad for a specific query. I am sure some users have trouble communicating why they think a specific result is good or bad.
However can people tell the general quality of a search engine? Absolutely. Google's simple aesthetics certainly helped them, but they didn't become the top search engine by luck and aesthetics alone. AltaVista, Yahoo, Lycos, Excite were all junk compared to Google, even the first version. It was very obvious.
The research I'm citing is from the late 00's. At this point in the game, differences in search relevance are in the measurement noise.
2. DDG has contact info. I maintain that it's better to send data directly to them if one is troubleshooting it or helping them improve the product. Hoping a random employee is on same tech forum is a stretch despite it happening here more often than average. So, if we all did search data, we'd post it on a dedicated forum they host after we email them about the project.
While these are all true, we're on a message board, not debating in Ancient Greece. I am very sympathetic to calls to improve comment quality, but on the other hand it's unrealistic to expect someone to perform a deep technical analysis of why Google is better... in a message board comment.