There are no settings for this. Should you want to remove it, you may create a template override and remove the DOM,

/wireframe/helpers/cover/group.php
[gist]
<?php if ($this->config->get('groups.sharing.showprivate') || (!$this->config->get('groups.sharing.showprivate') && $group->isOpen())) { ?>
<div class="btn-group">
<?php echo $this->html('group.bookmark', $group); ?>
</div>
<?php } ?>
[/gist]

/wireframe/helpers/cover/page.php
[gist]
<?php if ($this->config->get('pages.sharing.showprivate') || (!$this->config->get('pages.sharing.showprivate') && $page->isOpen())) { ?>
<div class="btn-group">
<?php echo $this->html('page.bookmark', $page); ?>
</div>
<?php } ?>
[/gist]

/wireframe/helpers/cover/event.php

[gist]
<?php if ($this->config->get('events.sharing.showprivate') || (!$this->config->get('events.sharing.showprivate') && $event->isOpen())) { ?>
<div class="btn-group">
<?php echo $this->html('event.bookmark', $event); ?>
</div>
<?php } ?>
[/gist]