Compare 2 classes. Class A expects all its dependencies to be passed as constructor parameters. Class B has a default no-arg constructor, but buried inside 5 of its methods calls Dep1 dep1 = new Dep1(); or Dep2 dep2 = new Dep2(); Now, which class has obvious and loosely coupled dependencies? Which class has hidden and tightly coupled dependencies?

To me, answer is clear - class A has obvious and loosely coupled ones. Lo and behold, class A comes from program which uses DI. Class B doesn't.