You are meant to find it slightly creepy and inhuman in general. Ender spends a great deal of the next three books self-flagellating.
(Which are, incidentally, not much like the first book. The first book was a juvenile sci-fi book, the next three are fairly serious works you wouldn't hand to a 12-year old and expect them to enjoy. Or understand, frankly.)
What I meant is that the children are comically pure, and utterly inhuman. Endlessly droning on about how much he loves his sister, never misbehaving or having a crush on a pretty girl; it all reflected a very strange impression of childhood.
(Which are, incidentally, not much like the first book. The first book was a juvenile sci-fi book, the next three are fairly serious works you wouldn't hand to a 12-year old and expect them to enjoy. Or understand, frankly.)