I do not disagree with this. I disagree with your contention that once sworn in, someone is legally a President although they are not eligible to hold the office. I asked you to find support of this position of yours. You still haven't. I have supported my contention from language found in the Constitution. You've yet to provide yours.
“I disagree with your contention that once sworn in, someone is legally a President”
A) that is what swearing in does, it makes someone President
B) any dispute about whether he can be President can ONLY be resolved through impeachment process. What proof do you have that he is not eligible? It would have to be presented before an impeachment trial, there is no other forum to decide it.
According to some birthers, Chester B Arthur was never eligible to be President. (I disagree.) Was he the President? Are the laws he signed valid? (YUP).