How to make page/post password protected so you must reenter everytime you visit the page?

Stop what you’re doing – it’s so much simpler!

function wpse_191369_post_password_expires() {
    return time() + 10; // Expire in 10 seconds
}

add_filter( 'post_password_expires', 'wpse_191369_post_password_expires' );

That’s all you need.