How is it that we cannot inject a service into a configuration block but can do so in a resolve?

Question

I am basically following a tutorial and wanted to understand why this code works.

This is my service:

app.factory('postFactory', ['$http', function($http){

  var obj= {
    postList:[]
  };

  obj.getAll= function(){
    return $http.get('/posts').success(function(data){
      angular.copy(data, obj.postList);
    });
  };
  return obj;`enter code here`
}]);

This is the resolve:

   $stateProvider
    .state('home', {
      url: '/home',
      templateUrl: '/home.html',
      controller: 'MainCtrl',
      resolve: {
        posts: function(postFactory){
        return postFactory.getAll();
        };
   )

The resolve calls the method getAll() on postFactory. I know that a resolve is reached in the code before the controller is initialized and therefore, the service. How does it then access the method at all? Also, as stated in this question and answer, AngularJS dependency injection of value inside of module.config,

A module is a collection of configuration and run blocks which get applied to the application during the bootstrap process. In its simplest form the module consist of collection of two kinds of blocks:

Configuration blocks - get executed during the provider registrations and configuration phase. Only providers and constants can be injected into configuration blocks. This is to prevent accidental instantiation of services before they have been fully configured.

So if we want to 'prevent accidental instantiation of services before they have been fully configured', why are we being able to instantiate them in the resolve?