Can’t sort custom column on user.php by number / meta_value_num?

Instead of ‘request’ function, use this :

add_action('pre_user_query', 'user_column_orderby');
function user_column_orderby($userquery){
if('Votes'==$userquery->query_vars['orderby']) {
global $wpdb;
$userquery->query_from .= " LEFT OUTER JOIN $wpdb->usermeta AS alias ON ($wpdb-   >users.ID = alias.user_id) ";
$userquery->query_where .= " AND alias.meta_key = 'wp__user_like_count' ";
$userquery->query_orderby = " ORDER BY alias.meta_value ".($userquery->query_vars["order"] == "ASC" ? "asc " : "desc ");
}
}