为什么要删除单个术语？

$existingTerms = wp_get_post_terms($postID, \'custom_taxonomy\');
        $newTerms = array();
        foreach($existingTerms as $term) {
            if ($term->slug != \'remove_this_term\') {
                $newTerms[] = $term->term_id;
            }
        }
wp_set_post_terms($postID, $newTerms, \'custom_taxonomy\');

wp_remove_object_terms($postID, \'remove_this_term\', \'custom_taxonomy\');