Google's search has been bad for a long time, esp. with older content. I had to use Bing to find a bug report from 2014 I was trying to find around 2 years ago.

It's a number of things like:

1. not searching for exact quotes/text, only words in the query;

2. including other lexical forms in the results (e.g. searching for things like "how do you open the run dialog" returns results for running (the sport/exercise) as well as run (an application));

3. including synonyms, typos, etc.

It seems like while each change makes sense and can improve results in some cases, over time the combined effect has made Google's search near unusable.