As virtually all early search engine developers have found out the hard way, it's extremely easy for website owners to cheat such a basic algorithm by spamming keywords.
Of course, around that time Duckduckgo started going downhill as well in this regard.
This is everything that's wrong with search in a single sentence.
"What's the name of the plant that that eats flies?"
This should, and does, produce results for Venus Fly Traps but I doubt any useful page contains all of those words.
If you were searching that sentence without the quotations I could get behind it return Venus Fly Traps results, but if you are using the double quotes you are trying to search for that EXACT string.
"What's the movie where the guy turns into a pidgin?"
This should return results for Spies in Disguise, and indeed, every search engine I tried does. I doubt any relevant page actually contains all the words in my query.