They could also request (but not order) Russia Today, Fox News, One America News Network, and Stormfront to do some basic fact-checking on the videos they host; but that would be a complete waste of the Senators' time, so they don't bother with the request.
And private entities should go even further, at least to protect their brands. I will always think of Facebook as the place where the Rohingya genocide was organized and carried out, and Facebook is where violent protesters like Kyle Rittenhouse gathered before killing multiple people. I think about the platforms that allowed ISIS to radicalize people. Google doesn't want YouTube to be the video hosting site where you can watch the world burn. Reddit removed the sub where you could literally watch people die. You might see these actions as against some dearly held political beliefs but it's pretty clear to me that these are just adults trying to act with a modicum of responsibility.