I like Dennis Prager. He is a pretty smart guy and generally right on the issues.
But here he makes the classic mistake of equating secularism with socialism leaving out the really successful secular system: capitalism. This is your basic red herring/paper tiger argument that compares the damage done in religious wars with the damage done in fighting against the Nazis and the Communists. What it is ignores is the non-wars between cooperating, secular or at least somewhat secular, capitalistic countries. And I include the U.S. in that latter category. The U.S. conduct of business and mutual defense is not based on our religious beliefs at all. For example, what do we have in common with the Japanese and Koreans in the religious realm? The answer is nothing. We have an agreement to trade and provide mutual defense. We don't fight them despite the fact that we do not share religious beliefs with them - it is a purely secular arrangement and is based on a common belief in the principles of capitalism more than any other philosophy.
Sorry Dennis, you are just dead wrong on this one.
You are 1) comparing apples and oranges, and 2) changing the subject.
1) Capitalism is not per-se secular.
Capitalism addresses only the economic aspects. You can be a Nazi capitalist. All capitalism changes is how you address economic risk, not how you order the rest of (and the larger part of) the lives of the citizenry.
You can also be a Christian capitalist. Capitalism flowered in the Christian world.
2) Whether or not capitalism is successful, it doesn't change the fact that secularist wars killed a lot of folks. On the religious side, the fact that Tibetan Buddhism didn't do wars, doesn't change the fact that Arabian Islam does.