I'm pretty sure that was just one crazy Jew and not a theory of the Jews.
You're correct in that most Jews won't openly say it in such a blunt manner - they usually think these kind of thoughts.
I hope Trad Guy asked a follow up question. The question would be "Hey, no credit at all for saving the Jews from Hitler's Death Camps? I mean, honestly, if it wasn't for the English and the Americans, Hitler would have killed even more." That would be a question to ask the guy.
Sometimes, especially online, people will engage in posturing where they say inflammatory things to get a rise out of others. However, what Trad Guy says is in line with Jewish thinking. If you don't believe this, go to a Jewish bookstore, look for an Artscroll Edition of the Chumash and an Artscroll Edition of the commentary on the Psalms and read through the commentary for the general mindset.
Having said this, I want to conclude that a small portion of Jews are actually on the decent side, although how could someone who orders their life in contradiction to Our Lord be considered "decent" I have yet to figure out.