Using the American military to defend other countries' interests makes you what?...not truly American
We share common enemies, if nothing else.
They are a normal, Western, nation. Made up of normal people who just want to raise their kids and bother no one, and thus, we, as another Western people who have the means to help, have a moral obligation to help them. Would you let a normal person drown, just because they are not your kin? Of course not.
They contribute much to the world. Google Israeli scientific and medical advances.
We promised to help them, and they rely on that promise. If we abandoned them, no one would ever trust us or work with us again.
They are an unsinkable aircraft carrier and beach head smack in the middle of the most critical area of the world.
So, yes, defending Israel is in America's best interests.