Remove Categories and Tags from Admin Dashboard

Just like @fatwombat suggested you need to rewrite the table. If you can’t modify the @Milo solution, here is a snippet that will remove the columns:

function my_manage_columns( $columns ) {
    unset($columns['categories'], $columns['tags']);
    return $columns;
}

function my_column_init() {
    add_filter( 'manage_posts_columns' , 'my_manage_columns' );
}

add_action( 'admin_init' , 'my_column_init' );