I think in part that Google just has gotten a spectacularly confusing failure mode. If it can't find good matching contents, it starts second-guessing your query and producing other results, which makes you think it's not even considering what you entered. It may even be "better" in the sense that it's more likely to return at least something relevant, but in practice it's bad UX because it's so unintuitive what's happening. It's probably one of those unfortunate optimizations that are invisible when they work and frustrating when they don't.
There is so much stuff on the Internet it's easy to start thinking there is guaranteed to be good results for any search, and that just doesn't seem to be the case. Especially with highly specified searches with 6-8 terms, you quickly enter the domain where you're reasonably unlikely to find an exact match.