Logic, How Does it Work?

If I understand the Birther Controversy correctly, the problem was that Barack Obama was born in Kenya and therefore could not be the president of the United States because he wasn’t a “natural born” citizen. His birth certificate that claimed he was born in a Honolulu hospital is a fake.

Okay, so following this logic, Ted Cruz’s birth certificate that shows that he was born in Calgary, Canada is proof that he, too, is ineligible to be president of the United States, and it doesn’t matter whether or not he pays $100, fills out a four-page form, and renounces his Canadian citizenship because he ain’t natural born.

Why is this so hard?