WordPressでquery_postsを使ってはいけない

// TOPページの記事一覧(index.php)で特定のカテゴリのみ表示
<?php 
query_posts('cat=カテゴリーID'); 
// ループ
if ( have_posts() ) {
    while ( have_posts() ) {
        the_post();
        // 処理を記述
    }
}
?>

/**
 * Sets up The Loop with query parameters.
 *
 * Note: This function will completely override the main query and isn't intended for use
 * by plugins or themes. Its overly-simplistic approach to modifying the main query can be
 * problematic and should be avoided wherever possible. In most cases, there are better,
 * more performant options for modifying the main query such as via the {@see 'pre_get_posts'}
 * action within WP_Query.
 *
 * This must not be used within the WordPress Loop.
 *
 * @since 1.5.0
 *
 * @global WP_Query $wp_query WordPress Query object.
 *
 * @param array|string $query Array or string of WP_Query arguments.
 * @return WP_Post[]|int[] Array of post objects or post IDs.
 */
function query_posts( $query ) {
	$GLOBALS['wp_query'] = new WP_Query();
	return $GLOBALS['wp_query']->query( $query );
}

function filter_category( $query ) {
    // 管理画面や、メインクエリ以外の処理に影響を及ぼさないように
    if ( is_admin() || ! $query->is_main_query() ){
        return;
    }

    if ( $query->is_home() ) {
        $query->set( 'cat', 'カテゴリーID' );
    }
}
add_action( 'pre_get_posts', 'filter_category' );