Simpplr Senior QA Automation Engineer interview questions

The interview was very good .I answered all the questions positively. At the last, he asked me about my current ctc . I told him is this necessary to tell you my last ctc but nevermind I shared my details with him. I believe an interviewer should not ask this questions only Hr person should take care of these things ,it impacts a lot on interview. Now a days knowledge is not a factor what matters is interviewer mind.He will decide based upon the salary so why hr are there in a company?