Add author box to all post types (except pages) and then remove it from "Snippets" Custom Post Type

functions.php

<?php

// Add author box to single posts and author archives
add_filter( 'get_the_author_genesis_author_box_single', '__return_true' );
add_filter( 'get_the_author_genesis_author_box_archive', '__return_true' );

// And remove it from anything that's not a post
add_action ('genesis_entry_footer', 'wpm_remove_author_box' );
function wpm_remove_author_box() {
  if ( get_post_type() == 'snippet' ) {
    remove_action( 'genesis_after_entry', 'genesis_do_author_box_single', 8 );
  }
}