You're kdding. Haven't you ever read Othello? Teenage girls are often attracted by exotic men who are slightly more mature. It's not that hard to envision a naive, idealistic 17 year-old from Kansas falling for a dark and dreamy 25 year-old African.
It's not like he was an illegal alien. He was on a full scholarship and had fairly good prospects. And it's not like he was all that much older. An 8 year age difference isn't a big deal. It's not like he was old enough to be her Dad.
As to his wife and kids back home, from what I had read, she was not aware of them. That he failed to disclose them to her was, in fact, one of the grounds for her divorce.
Come to think of it, that he was a bigamist makes it even more absurd to suggest that he took her back to Kenya to give birth. If he were hiding the fact that he was already married and with kids, why the heck would he take her back to his family and run the risk of her finding out?
That's just plain loony.
I've seen the photos of the man. Dark he was, very, but dreamy, not hardly. His son is much better looking. IMHO, he looks mostly like a darker complected version of his maternal grandfather.
But even if she was "naive and idealistic, she still wasn't in her right mind, by the standards of the day especially.
But you make my point, if she was that enthralled with the Luo dude, she'd have gone to Kenya if he told (much more likely than "asked", which is what I typed first) her to.
BHO Sr, himself was no common sense kind of guy. A big dreamer and apparretly like Sam Houston, a Big Drunk. Houston had the advantage that horses generally don't crash and kill you if you ride drunk. :)
To him, and under the law in Kenya, even though it was a British Colony, there was no stigma in being a polygamist, even though it apparently did not sit well with some of the Obama wives, others were OK with it, such as his third wife, who was another American woman from the Boston area, Ruth Nidesand. He took her home before marrying her. So apparently wife one was mostly OK with it, and wife III was as well, although she may have soured on it later. Why would a naive idealistic 17 y/o also not be OK with it? At least in theory.