Because nearly all previous presidential candidates lived public and verifiable lives. No one could conceive of a fraud with the cojones to run. Chester A Arthur fiddled with his fathers foreign birth. Can't think of any others except the Bamster. Some say John McCain didn't meet the standard due to not being born on US Territory. A US military base would be considered US territory but McCain was born in a US military hospital that sat on land leased from Panama. So the story goes
I wasn’t for McCain, only voted for him for obvious reasons BUT he went through the whole vetting process and even legal hearings to prove he was natural born, when the question was posed. Supposedly zero even assisted him in that. The point is, why didn’t zero go through the same legal process?