>One former contractor the WSJ spoke with described down-voting any search results that read like a "how-to manual" for queries relating to suicide until the National Suicide Prevention Lifeline came up as the top result. According to the contractor, Google soon after put out a message to the contracting firm that the Lifeline should be marked as the top result for all searches relating to suicide so that the company algorithms would adjust to consider it the top result.
>Or in another instance, sources told the WSJ, employees made a conscious choice for how to handle anti-vax messaging:
>One of the first hot-button issues surfaced in 2015, according to people familiar with the matter, when some employees complained that a search for “how do vaccines cause autism” delivered misinformation through sites that oppose vaccinations.
At least one employee defended the result, writing that Google should “let the algorithms decide” what shows up, according to one person familiar with the matter. Instead, the people said, Google made a change so that the first result is a site called howdovaccinescauseautism.com—which states on its home page in large black letters, “They f—ing don’t.” (The phrase has become a meme within Google.)
https://arstechnica.com/tech-policy/2019/11/google-search-re...
tl:dr - Human oversight / manipulation.