gistfile1.txt

// ==UserScript==
// @name         PeaceAndQuiet
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Speak freely in robin chats.
// @author       DC-3
// @match        https://www.reddit.com/robin
// @grant        none
// ==/UserScript==

(function() {
    'use strict';
setTimeout(function(){
var target = document.querySelector('#robinChatMessageList');
var observer = new MutationObserver(function(mutations) {
    mutations.forEach(function(mutation) {
        var msg = $(mutation.addedNodes[0].lastElementChild).text(); 
        if((!msg.startsWith('[')) && (!msg.startsWith('[robin]'))
        ) {
            mutation.addedNodes[0].style.display = "none";
        }
    });
});
observer.observe(target, {childList: true});
}, 20);

})();