SpaceX Software Engineer(Internship) interview questions

There was 1 phone screening, 1 technical test, and 1 phone screening. Working with the HR team was a great experience. They were kind and quick to respond. However, the interview with the Software Engineering team was a bad experience. The technical interview wasn't ready on the day of the interview, so it had to be delayed. The specification was very generic, so I didn't know what they were specifically looking for. Yet, I passed. For the final round interview, I was assigned to one of the higher-ranking officials, and he delayed the interview 3 times until he reassigned my interview back to the initial lead engineer I had interviewed with. The interview was further delayed 2 times, and eventually, a senior engineer interviewed me. He even complimented my code from the second-round interview, and I thought everything went great for the final round interview. I expected to pass. After not passing the final interview round, I sent an email asking for feedback on how I could improve so that I could better prepare for my next interviews. The interviewer did not directly respond, but instead had an HR team member reply that I should work on my technical skills, especially the language I used. Wait, wasn't that the whole point of the second-round interview? I passed and he even complimented my code. The team also mentioned that they are very busy, so they requested that questions not be sent directly to them, but only responded to through the HR team. I'm not sure if this is the norm, but the whole interview process felt quite disrespectful to me. I tried to be as patient as I could, but I wasted a significant amount of time on this disrespectful interview process. If my technical skills were an issue, why did I pass the technical interview in the first place? I don't even understand. Is this even right?