I'm doing some basic API testing and notice that restricting my new route to GET doesn't work. POST requests also go though using Postman. (PUT, PATCH, DELETE do not however, displaying a "no matching route/method" error):

function displayDummyData() {
  return 'dummy data'; // responds 'dummy data' on POST request
}

function checkIfAnyone() {
  return true;
}


function registerDummyRoute() {
  register_rest_route('wp/v2', 'tut', [
    'methods' => 'GET',
    'callback' => 'displayDummyData',
    'permission_callback' => 'checkIfAnyone'
  ]);
}
add_action('rest_api_init', 'registerDummyRoute');

How can I restrict this route to only GET requests?