Getting this code to work in Multisite

I’d like to run this code via cron on multisite. When I use the admin_init hook the code executes and works perfectly, deleting the blogs, however when I set it as a cron, and then run the event with the WP Crontrol plugin, the blogs don’t get deleted. What gives?

register_activation_hook( __FILE__, 'remove_blogs_activation' );
    /**
     * On activation, set a time, frequency and name of an action hook to be scheduled.
     */
    function remove_blogs_activation() {
        wp_schedule_event( 1386979200, 'daily', 'remove_blogs_hook' );
    }


    add_action( 'remove_blogs_hook', 'remove_blogs_daily' );

    function remove_blogs_daily() { 
        $all_blogs = wp_get_sites();    

        foreach ( $all_blogs as $key => $val ) {

            $blogs_to_keep = array( '1','2' );
            if ( ! in_array( $val['blog_id'], $blogs_to_keep ) ) {
                wpmu_delete_blog( $val['blog_id'], true );          
            }

        }
    }

The new code I’m using, to also clear the users:

    <?php



    register_activation_hook( __FILE__, 'wpchat_clear_sites_activation' );
    /**
     * On activation, set a time, frequency and name of an action hook to be scheduled.
     */
    function wpchat_clear_sites_activation() {
        wp_schedule_event( 1386979200, 'daily', 'daily_clear_sites_hook' );
    }


    add_action( 'daily_clear_sites_hook', 'wpchat_clear_out_sites_daily' );
    /**
     * Clear out the sites and users
     */
    function wpchat_clear_out_sites_daily() { 
        require_once( ABSPATH . 'wp-admin/includes/admin.php' );
        require_once( ABSPATH . 'wp-admin/includes/user.php' );

        if( ! function_exists( 'wpmu_delete_blog' ) ) return;

            $users_to_keep = array( '1','4','43' );

        $blogs_to_keep = array( '1','4' );

        $all_sites = wp_get_sites();    

        // Remove all blogs except for the main blog and the template blog
        foreach ( $all_sites as $key => $val ) {

            $users = get_users( array( 'blog_id' => $val['blog_id'], 'fields' => ID ) );

            // Remove all users except for the test site admins
            foreach ( $users as $user) { 

                if ( ! in_array( $user, $users_to_keep ) ) {
                    wp_delete_user( $user['ID'] );
                }
            }

            if ( ! in_array( $val['blog_id'], $blogs_to_keep ) ) {
                wpmu_delete_blog( $val['blog_id'], true );          
            }

        }
    }

    register_deactivation_hook( __FILE__, 'wpchat_clear_sites_deactivation' );
    /**
     * On deactivation, remove all functions from the scheduled action hook.
     */
    function wpchat_clear_sites_deactivation() {
        wp_clear_scheduled_hook( 'daily_clear_sites_hook' );
    }