well you went in a different direction here. You're no longer talking about the social media platforms "censoring" their own content and how that violates your freedom of speech--essentially because they have become the de-facto popular speech platforms. Let's stick with that subject first.
Thing is, I don't disagree with you. At some point, when these platforms become (as they pretty much have) the primary means of communicating between individuals and, apparently, disseminating news, they march into a grey area between private company and public trust. They certainly aren't regulated (they don't have to pay license fees and head to SEC guidelines) like media organizations, so it's the Wild West for them. And, as determined by our market economy, they get to make their own rules to govern this ostensibly lawless enterprise. I agree with you that this sort of governance becomes dangerous when they have become the defacto gateway of information.
So, essentially, they need to be regulated similarly to media. At the same time, there needs to be a public trust that the information you receive is real information, not nonsense from a troll farm. Simply being fed what you want to hear, regardless of veracity, doesn't do you any good despite how it makes you feel. It doesn't do anyone any good. Perhaps there are better platforms for that and if that is what you want, then it isn't at all what you are arguing for here. I doubt that algorithms are the best way to solve this problem of separating truth from lies with such accounts, but it is a way. The other option is to get around these pesky licenses that require ethics in information dissemination by declaring yourself an "entertainment platform" to the SEC, which is exactly what FOX News does. They don't have to worry about bothersome issues of ethics and source-based vetting of information, because they aren't beholden to the same guidelines that govern network media, NYT, Washington Post, etc. You know, the actual media.
It sounds like what you want is government regulation to insure that social media meets standards that real people are protected to blather about their nonsense (media) but, that there is no oversight to discern between what is clearly fake and what isn't (FOX). I think you have to chose one.