Interviewers don't give most candidates tangible feedback/criticism because the vast majority do not want it. People who just bombed an interview usually know

Interviewers don't give most candidates tangible feedback/criticism because the vast majority do not want it. People who just bombed an interview usually know it, and aren't in a place to receive constructive feedback. The rare few who handle that well should explicitly ask for feedback or critique. I always give this when asked, but never offer it unasked.