No one disputes that there are constitutional qualifications to be president. Does anyone seriously claim that the voters and their electors are somehow incapable of applying those standards to candidates? Does anyone seriously claim that, even though the Constitution states that the president shall be selected by the electors, that the Founders secretly meant that the electors could choose only among candidates approved by the Supreme Court?
The voters and their electors are the final judges of the candidates' qualifications. If you want to argue that a candidate is unqualified, make your pitch to the voters and to their electors. In the case of selecting presidents, they are, in the words of one of my favorite recent presidents, the "deciders."
If you don't like that process, it can be changed through constitutional amendment and you can change the constitution so as to require each candidate to be screened by the Supreme Court or by a committee of librarians. But, until its changed, please accept the Constitution's procedural rules.
If the voters decided that Vladimir Putin should be the US President, would that be a violation of the US Constitution which says that only a natural born US citizen is eligible to be President, and that if a “President elect” (that is, one already chosen by the electors) fails to qualify by the beginning of the term he/she may not “act as President”?
The 20th Amendment makes absolutely clear that what you are saying is unconstitutional, because it directly provides for the situation where the voters have made their choice and the person they chose DOES NOT QUALIFY. The 20th Amendment clearly says that the person they chose - but who fails to QUALIFY - must NOT act as President.
To go with your view would allow a simple majority in a Presidential election to UNDO THE 20TH AMENDMENT - that is, to AMEND what the Constitution means, in contradiction to what the ratified 20th Amendment says. What you are saying is that a simple majority vote of the public can reverse the meaning of a Constitutional amendment.
Can a simple majority in a national vote get rid of the freedom of press, or any of the other Constitutional amendments? Because - after all - the voters are the ones given the task of interpreting the Constitution, right? All the stuff we Americans have been told about the 3 branches of government with their respective roles of making law, implementing law, and interpreting law.... is all a bunch of hooey, right? Really it’s all just the average ordinary illiterate bum on the street who is supposed to do all those things, whenever they vote. Right? ‘Cause that’s what you sure seem to be saying.