Like Obama, I have the feeling that his mother kept telling him that he was "brilliant" and "special", but never really corrected him/taught him how to behave.
Your explanation is probably closer than mine. Both of my sister's kids seem a little socially awkward probably because they advanced so quickly that their classmates were years older than they were. But their personality traits come across different than Ted's.
I know I am going to catch some heavy flack by mentioning this, but Cruz makes the hair stand up on the back of my neck. Another famous Ted, Ted Bundy grew up a couple miles from where I grew up. His mother went to the same church that we did for a few years. I don't remember Ted Bundy at all but my parents knew his mom pretty well. She worked for my great Uncle Ed for a while. My dad used to ponder about Ted Bundy frequently to me after he got caught and he said that there was always something creepy about Ted Bundy that made the hair stand up on the back of his neck. I really wasn't sure what he meant until this election season.
I am glad that whatever it is with Ted Cruz caused him to become a lawyer and get into politics instead of stalking and killing women. But as much as I tried to get myself to like him early on... I can't really seem to shake the feeling that there is something not quite right about him. This certainly could be more a reflection on myself and just some subconscious memory whose source I am not completely aware of. So I will put on my foil hat and shut up now.