The link you gave is not indexed on archive.org. This is the one that is
indexed:
https://web.archive.org/web/20120121180305/http://www.muktware.com/bitsnbytes/3058
Though considering the article doesn't say anything substantial, I don't know
why you even referenced it. It's the video which is the original source.
I can tell exactly why DDG didn't return LibreOffice as a result at the time:
the video author searched for "open source office suite". LibreOffice doesn't
advertise itself as "open source" very much. Not that it matters anyway,
because it's not true anymore:
https://trisquel.info/files/Screenshot from 2017-02-17 08-29-50.png
As for Firefox, I don't get Firefox immediately in the results of either DDG
or Google (unless you count the Wikipedia page for Firefox, which only DDG
shows). In fact, the results suck for both of them. The first result on
Google and the fifth result on DDG is an article purporting to list the "11
best open source Web browser", but it actually links the proprietary Google
Chrome and Opera browsers in the top three alongside Firefox, and the first
result on DDG similarly lists Google Chrome, but it's a little better since
it doesn't list Opera or Pale Moon.
So let's summarize everything here:
1. The first claim is demonstrably false.
2. The second claim is a half-truth, but the problem with the search results
on both search engines is inclusion of proprietary Web browsers, not
exclusion of a non-libre browser that is considered to be "open source". And
that seems to be caused by idiots who think that Google Chrome is "open
source", not by a problem in the search engines.
