The moment you realize a company is only a machine concerned with turning a profit and not an actual person you interact with and expect politeness and humanity out of, you'll stop feeling offended by companies ghosting you.
When a company sends you a letter to tell you your application has been rejected, it's only a courtesy extended to you by a HUMAN HR person who actually cares about behaving decently, not by the company. So enjoy the gesture when it happens, but simply ignore it when it doesn't.