Fighting the Extremes

Social media companies such as Facebook and Twitter are wanting to censor extremist speech and point of views in the name of combating terrorism but they have purged accounts belonging to conservative groups as well.
These social media giants want to limit or eliminate so-called “fake news” and “hate speech” and this gained traction following the election of Donald Trump.
But how is hate speech, fake news and extremism defined and who gets to define it as these companies are private and not truly subject to the first amendment.
Should Christian and conservatives be starting their own type of social media and can there really be free speech without the Lord?