Google's annual spam report for 2019 said its preventative spam efforts resulted in over 99% of search results being spam-free and that it found 25 billion pages discovered every day are spammy. Declaring that "Every search matters", Google acknowledges that disruptive behaviours and spammy content degrade the qualilty of search results. It has teams in place to identify and prevent spam from appearing. The report details how Google fights spam at scale (that's where the 25 billion spammy pages number comes from). In 2018, Google significantly reduced user-generated spam and hacked websites are less common. However, it sees an increase in auto-generated and scraped content, which can not only annoy but actually harm users.
Beyond catching spam, Google is also rooting out scams and fraud, partly by looking at the queries most likely to return search results that include sites designed to trick users by appearing to be official and authoritative. Google wants to enlist the help of webmasters in its efforts to have a spam-free environment. The first step is detection, then stop them, either via its automated system or by manual actions.