Intralox Customer Service interview questions

It was very pleasant until I was called to make an appointment for the next interview. At the end of the call, I was told that the original position I applied for was filled yesterday but that I am now in the process for another one. It was mentioned with such a taken-for-grantedness that I felt like their true colors were finally shining through. I wanted to stop the application procedure right then and there but the very nice HR lady convinced me to continue. After the next interview, I was told that they were unsure about my motivation because I was hesitating before the 2nd interview. Why do you convince me to continue the interview process just to use my reluctance as a reason not to make an offer? The other reason was my over-qualification and that they are afraid I might leave for a better position soon. All reasons that were known at the beginning of the hiring process. All in all, it was completely absurd, unprofessional and a waste of my time. My panel interview was also very questionable. The recently hired customer service lead from South America became noticeably insecure during the discussion. This led her to ask stupid questions like "How can we know that you are not gonna leave in a months after hiring you?" She was visibly threatened by my (if I may say so) smart answers, which I believe contributed drastically to my rejection. Or maybe I did a bad job at hiding my despise for people with this mentality...