That you probably don't want the thing you're searching for, but some alternate spelling, even if it's something completely different.
I imagine this probably ends up being the case for the majority of their users, but for advanced users and people searching for specific technical strings, they've cheapened their service.
> we didn't make any change *in terms of retrieval*
Users don't care which part of the system was changed to cause the results to be worse.
It looks like maybe your reply is only about what changes recently shipped and are mentioned in the blog post. A lot of the discussion in this comment section is about changes much older than these changes.
It may be true that quotes are working the way we expect, but the data set to which they apply is very obviously restricted before they get a crack at it.