It's not hypothetical. It's your assertion of what the constitution stands for. Kids born on US soil to two non-citizen parents, then moved to the parents' native land and raised there, is constitutionally qualified for the presidency. You find that to be an effect of the 14th amendment.
Your contention that "Any third generation person born in America to two parents who were born in America [and grandfather was a Euro citizen] is a dual citizen" has got to be an April Fools joke.
Not a joke at all, I have the second passport to prove it.
And by the way, it is hypothetical--we haven't yet had it happen so we haven't yet seen a court rule. When we do, bet that the court will hold the kid "natural born".