My History teacher has an extreme hatred of communism. What can I do?

First off, I am not a communist. However, I see the potential in the system, and can respect what communists are thriving for: true equality.

However, my history teacher hates communism. And I mean HATES communism, with a passion of a thousand suns. He spent an entire 2 hour lecture on why communism is a failure. He ridiculed Karl Marx and everyone who is a communist with very personal attacks, which in any country but the USA is crossing the line.

I would have argued against my beliefs to try to challenge his hateful arguments, but there's a problem: all most his entire family died under Stalin. He is the surviving sibling of his family, and he blames it purely on communism. I don't know how to argue with a man who lost his family under a communist regime. He has addressed the "we haven't tried real communism" arguement with a painful lecture on the millions of deaths under every communist country ever.

How should I approach this? Or should I just leave this one alone? I can guarantee another rant against communism, and I would like to bring up some valid points without him becoming furious at me for insulting his family.