Please note that the US code you are quoting is in effect now, but the code that matters is the code from the time of Obama’s birth. My understanding is that up until 1986, children whose birth matched his (alleged) situation would NOT have been considered citizens. Specifically, I think that item (g) in the code you quote was once worded differently and would have excluded a child born to a 19-year-old American citizen, if the child were born in a foreign country.
Plus, there is the “natural born” issue.
I think people are confusing the citizen with natural born citizen.
There is nothing illegal about Obama holding dual citizenships or even just being a citizen. But there are specific requirements to become POTUS.