You can complain about what people post, sure, but demanding people use content warnings is a form of gatekeeping.
You can mute any account you like if you don't like their content, but instead you wish those accounts only post things you'd like to read.
By trying to control what other people post I assume you don't quite understand how social media works.
Edit: I'm really just talking about CWs for people posting about political news and commenting on it.