Rude is one thing. This is quite another.
Would she have preferred that he spend his time chatting up the receptionist or thinking about his job? Not talking to people is not being dismissive. You may have something on your mind, (like a job interview) and be nervous which leads you to being taciturn.
That is ok. He would not have enjoyed working for her in any case. She wanted a chatty cathy.
That might depend on what the position is for. If it involves interacting with the public, it would be an important factor.