They (search, social media, advertising companies) are gaining a monopoly on truth. With that they indirectly control the government, which is the one with the monopoly on violence.
To emphasize, all human productions are biased, that's human nature, and news media are not exempt, despite many outlets making serious attempts to produce unbiased news.
Part of the job of being a consumer of media is understanding the bias of what we're consuming, determining whether it skews the news, and possibly counter-balancing by consuming other media with different bias. And yes, it's lots of work and most people aren't willing to spend the time doing that.
