How to remove nodes site wide from the toolbar on multisite install

To get all blogs/subsites a user is registered to, use get_blogs_of_user()

$sites = get_blogs_of_user( get_current_user_id() );

This will fetch all sites that aren’t marked as archived, spam or deleted. This will as well work in a single site environment, returning a an array with a single numerical key that has a stdClass object as value:

$sites = array( 0 => stdClass
    userblog_id -> $blog_id
    blogname    -> get_option('blogname')
    domain      -> ''
    path        -> ''
    site_id     -> 1
    siteurl     -> get_option('siteurl')
    archived    -> 0
    spam        -> 0
    deleted     -> 0
);

If it’s a multisite environment, it will use get_blog_details() to fetch the sites details.

---

Note that there’s a filter at the end (right before it gets added to the cache) of the get_blog_details() function to adjust the returned details:

$details = apply_filters( 'blog_details', $details );

---

Note that there’s a filter at the end of the get_blogs_of_user() function that allows you to adjust the returned objects:

return apply_filters( 'get_blogs_of_user', $blogs, $user_id, $all );

---

You could then adjust your admin bar nodes with something along the following lines:

<?php
/** Plugin Name: WPSE (#165787) Remove Admin Toolbar Comments, Dashboards, Media & Logo */

add_action( 'admin_bar_menu', 'remove_toolbar_items', PHP_INT_MAX -1 );
function remove_toolbar_items( $bar )
{
    $sites = get_blogs_of_user( get_current_user_id() );
    foreach ( $sites as $site )
    {
        $bar->remove_node( "blog-{$site->userblog_id}-c" );
        $bar->remove_node( "blog-{$site->userblog_id}-d" );
    }
    $bar->remove_node( 'new-media' );
    $bar->remove_node( 'wp-logo' );
}

Note that above plugin isn’t tested, so you might need to var_dump( $site ); in the foreach() loop and $bar to see if you are removing the right nodes (or any at all).