Yes, but humans are emotional beings, and we must recognize this. Sure, it is his fault he is so ignorant, but the difference between calmly explaining to him what is wrong with his thinking, and making fun of him, is that you hurt him on an emotional level. One must always live on both planes, and must always recognize what kind of argument he is dealing with. Emotional arguments are things to stay away from, because they only strengthen a person in the sense that bullying someone strengthens them, as opposed to teaching them KaraTe. People are tested in the little things. The unimportant things. That is where your personality shows. (BTW, how can you like this, and hate Gemara?)

Truly there is no moral or scientific evidence to the existence, or nonexistence of the Jewish god (which is not the same as the Christian god; I have not thoroughly studied that one yet, so I cannot make assumptions upon it). The god, as a non-material being that is not confined to space or time, cannot be properly defined by humans, especially when Jewish texts, and more importantly Masoret (tradition; more accurately inherited information not by means of writings), give us very little information about god (bear with me here, I know this is a bit abstract). That is why all scientific definitions of god are so vague. No one has ever bothered to tell us (I mean religious Jews) what god is, and quite frankly, it does not matter. What matters in Judaism is not the Belief in god, but the Law (Belief is, of course a basis to that Law, but if we take into account that god cannot be proven or dis-proven, that if it were the case, it would have been done, belief becomes less critical). In Israel, for example, 90% of Jews believe in the Jewish god, but only one-third of them follow Jewish law (that is, Orthodox Judaism). The rest keep some of the laws, like Shabbat, or Kashrut, but only those they choose, and they may change their opinions many times. This is because, Judaism is not belief, rather it is "kabalat ol malkhut shamaim" (קבלת עול מלכות שמים) (roughly=Acceptance of the Burden of the Kinghood of God). Those who are religious not only believe in god, they accept a long list of rules, rules that guide their society, way of thinking, and morality.

In WWII, near the end of the Pacific Campaign, two speeches were made. One by Eleanor Roosevelt, and one by Hideki Tōjō. Each of them spoke, to their people, of why the campaign was necessary, why they should continue their support.

Roosevelt’s speech went something like “A glass of milk for every child”, while Tōjō reminded the people that despite the many losses, they were fighting to “preserve the honor of the Emperor” and that theirs was a noble sacrifice. We see here two totally different values: On the one hand, the needs of the people, on the other hand, the honor of the Emperor. These values were used to convince people of opposite justifications: The American, and the Japanese.

The amazing thing is that these speeches worked. The Japanese truly believed in the honor of the Emperor as a principle worth dying for, while the Americans truly believed in “the needs of the people” as a principle worth dying for.

If, say, an American said to a Japanese man and said to him: “But what of the starving children?” He would answer “Who cares! What of my dishonored Emperor?” People choose their principles, not by using logic, but rather base their logic on their highest principles, and from them glean new, sub-principles.

In short, so long as your religion does not give you science to learn (which will undoubtedly be disproved and proved again through the ages), but principles to follow, the only reason for you to leave that religion would be that you do not hold those as your highest principles, and therefore it is only a matter of time before those principles clash with your highest principles.

The reason one does not believe, is that he believes differently.