Lumen Java Full Stack Developer interview questions

Till round one of interview, everything was smooth and good. At technical round two, the interviwer asked me about a platform which was not mentioned in JD and which I was also not aware. As I was not aware, I told I havn't worked on it and not aware. But he started questioning deeper on the same topic. What is the point in asking questions on the same topic after I tell him I am not aware of it? He asked 2 to 3 questions on the same topic for 10 more mins and he said the interview is over. I don't understand why to conduct interview like this? It felt like he came with the intention of rejecting only.