hide-bp-user-from-member-directory-page-by-user-role.php

<?php
/**
 * Hide Users from BuddyPress Members List by User role.
 *
 * @param array $args Args.
 *
 * @return array
 */
function wbcom_hide_members_from_member_lists_by_user_role( $args ) {
	
	if ( is_admin() && ! defined( 'DOING_AJAX' ) ) {
		return $args;
	}

	$excluded = isset( $args['exclude'] ) ? $args['exclude'] : array();

	if ( ! is_array( $excluded ) ) {
		$excluded = explode( ',', $excluded );
	}

	$role     = 'administrator';
	$user_ids = get_users(
		array(
			'role'   => $role,
			'fields' => 'ID',
		)
	);

	$excluded = array_merge( $excluded, $user_ids );

	$args['exclude'] = $excluded;

	return $args;
}

add_filter( 'bp_after_has_members_parse_args', 'wbcom_hide_members_from_member_lists_by_user_role' );