wp-exclude-emoji not working

<h3>Plain HTML:</h3>
<div><button class="wp-exclude-emoji">◀</button></div>
<h3>Added by JS immediately:</h3>
<div class="replace1"></div>
<h3>Added by JS on timeout:</h3>
<div class="replace2"></div>

<script>function replaceDiv(divToReplace)
{
var dButtonLeft = document.createElement('button');
dButtonLeft.appendChild(document.createTextNode('◀'));
dButtonLeft.className = 'wp-exclude-emoji';
divToReplace.parentNode.replaceChild(dButtonLeft, divToReplace);
}
replaceDiv(document.querySelector('div.replace1'));
setTimeout(function(){replaceDiv(document.querySelector('div.replace2'));}, 1000);
</script>