To remove it from the DOM completely you’d have to override the about page template in a theme… there’s some detail about how to do that here: Overriding Discourse templates from a Theme or Plugin
The default template is this one: discourse/about.hbs at 9e440dca332c0e2879a1a6a4ee49347aba33d1ef · discourse/discourse · GitHub
And to override you’d want to copy the contents of the above file, add them to {theme}/javascripts/discourse/templates/about.hbs
, and modify as you see fit. You could remove all admins by simply removing this block…
{{#if this.model.admins}}
<section class="about admins">
<h3>{{d-icon "users"}} {{i18n "about.our_admins"}}</h3>
<AboutPageUsers @users={{this.model.admins}} />
<div class="clearfix"></div>
</section>
{{/if}}
If you wanted to remove only some admins you’d probably need to override the route to add your own filter (the default route is here: discourse/about.js at 098ab29d4150a5a39880d59ef6cad5f6795a18fd · discourse/discourse · GitHub)