Do you need to be polite in an interview?

Today I interviewed with a small pahrmaceutical company that I am interested in working for if they can make the numbers line up for me. All in all I had a good experience in the interview it was pretty typical, decent manager (young and a little arrogant) and my territory partner would be a great guy that I really like as a person.
That being said something was said today in the interview that rubbed me the wrong way and I let it slide and now I am kicking myself. The manager asked me why I have jumped jobs so many times. "Jumped jobs, I have not jump jobs." Granted the position I am currently in I have only had for six months, but it is somewhat unstable and it is a contract that could go bye bye. Before that I was with a major pharma company for about the last 4 years. I left that job based on poor management and my current position gave me such an increase in base salary it changed my life. Prior to the major pharma company I was on another contract that was going to be dissolved. So why is that jumping? I have moved up, made more money and had some longevity in my previous position. He asked why I was persuing a position with his company, and what would I do when the next guy came offering 5k more than him. I was offended, they recruited me. They asked some of my current customers for refferals and I was brought to their attention and they contacted me. I had even told them that I was not looking to move but I would hear them out, and know I am job hopping. Up yours a@@hole! is what I wanted to say but instead I said "does that answer your question sufficiently" what an a@@hole.
I am hating myself for this I shouldn't have even put myself in this position because they don't deserve me. I am a top performer with great relationships I don't need this crap. Why am I explaining myself to a guy with the same amount of experience as myself, especially when I am not unhappy in my current job. I am such an a@@hole. It is such a shame because my would be partner was a swell guy.