Facebook has been criticised for its stance on free speech and wider civil rights in a self-commissioned audit into its policies and practices.

Auditors highlighted a number of “serious setbacks”, saying they found the social network’s prioritisation of free expression over all other values, such as equality and non-discrimination, “deeply troubling”.

“Elevating free expression is a good thing, but it should apply to everyone,” said the two-year report, led by civil rights experts Laura W Murphy and Megan Cacace.

“When it means that powerful politicians do not have to abide by the same rules that everyone else does, a hierarchy of speech is created that privileges certain voices over less powerful voices.”

Facebook has been “far too reluctant” to adopt strong rules to limit misinformation and voter suppression while having no qualms addressing proponents of the anti-vaccination movement, or limiting misinformation about coronavirus, the report went on.

The decision to keep three posts by US President Donald Trump – one propagating hate/violent speech and two facilitating voter suppression – caused “considerable alarm” for the auditors and the civil rights community.

The report continued: “The auditors vigorously made known our disagreement, as we believed that these posts clearly violated Facebook’s policies.

“These decisions exposed a major hole in Facebook’s understanding and application of civil rights.

“While these decisions were made ultimately at the highest level, we believe civil rights expertise was not sought and applied to the degree it should have been and the resulting decisions were devastating.

“Our fear was (and continues to be) that these decisions establish terrible precedent for others to emulate.”

The audit’s release comes amid a challenging period for Facebook in which hundreds of companies have agreed to temporarily halt advertising on the platform as part of the #StopHateForProfit boycott.

Organisers said they were disappointed after engaging in talks with Facebook bosses about the issue on Tuesday.

Reacting to the report’s findings, chief operating officer Sheryl Sandberg said: “We have made real progress over the years, but this work is never finished and we know what a big responsibility Facebook has to get better at finding and removing hateful content.

“The audit looked at a wide range of civil rights issues, including our policies against hate.

“There are no quick fixes to these issues – nor should there be.”

The report acknowledges that Facebook has made progress in addressing some key issues, but said it has “not yet devoted enough resources or moved with sufficient speed to tackle the multitude of civil rights challenges that are before it”.

“While the audit process has been meaningful, and has led to some significant improvements in the platform, we have also watched the company make painful decisions over the last nine months with real world consequences that are serious setbacks for civil rights,” it reads.

Among the improvements Facebook has made are a commitment to bring civil rights expertise in-house, as well as banning ads that are divisive and include fear-mongering statements, and expanding its voter suppression policies.