> By that reasoning, a presidential candidate of Chinese descent who was a natural born American citizen but had relatives back in china would be disqualified

If large numbers of voters felt that, then they would never get elected.

> nowhere justified by the constitution

The voters are entitled to vote however they like; that's implied by the constitution.

> I accept that I do not qualify for a high security clearance because I’m married to a Chinese national

Then you essentially agree with me.

> I don’t think that should have any bearing on any other jobs that don’t require such clearances

I agree. The question is, which jobs should require such clearances?