Disable Helpful in a specific term of a taxonomy

functions.php

<?php

/**
 * Disable helpful on new posts with specific term of taxonomy.
 *
 * @param int $post_id
 * @param WP_Post $post
 * @param bool $update
 *
 * @return void
 */
function hide_helpful_on_new_posts( $post_id, $post, $update ) {    
    if ( $update || wp_is_post_revision( $post_id ) ) {
        return;
    }

    /* to change: term from taxonomy */
    if ( ! has_term( 'term', 'taxonomy', $post_id ) ) {
        return;
    }

    update_post_meta( $post_id, 'helpful_hide_on_post', 'on' );
}

/* init hide_helpful_on_new_posts on post save */
add_action( 'save_post', 'hide_helpful_on_new_posts', 10, 3 );

Related links

• https://developer.wordpress.org/reference/hooks/save_post/
• https://developer.wordpress.org/reference/functions/has_term/
• https://developer.wordpress.org/reference/functions/update_post_meta/