And here is the crux of the issue. Private platforms may restrict speech. There are limits that may be enforced. Child pornography is one such limit.
A private platform may restrict speech. I have been banned from certain gun boards because I espoused positions in opposition to unrestricted gun ownership. That is reprehensible and speaks to their intolerance and inability to tolerate other opinions.
They are within their right to restrict what is said. Facebook, Twitter, all of the social media platforms have rules which you agree to abide by. Failure to do so will result in your account being suspended. This has happened to Alex Jones for failure to abide by the user agreement on Facebook.
Sites like this aside...Social Media is the new forum. It is where ideas, especially political ones are formed, argued, and distributed.
Now the NRA is directed towards guns. This site is directed towards sex...so your argument totally stands there.
But Facebook, Twitter, Youtube, they have become so much more than just social media sites, the are the new forum even more so than television. Because of that they should be morally obligated to obey a more Millian look at speech.
Being as important as they are, shadow bans of any view is restricting the public forum. All that does is cement views and encourage echo chambers.
Your political views should be fluid, and it should be fluid because you hear more than one side all the time. Once they become concrete, you aren't thinking, you're reacting.