Agree. I know there's some Israelis using this course to learn English so while I have no idea if this is maybe the case in Hebrew too but in English, in most cases saying "He's not a normal boy" would be rather offensive. Unless we're talking about Harry Potter or something where it's clear you mean better than "normal".
I suppose a lot is in tone as well (and assume that would true with the sentence in Hebrew as well) but just stood out to me as I guess it did to you.
that's not very impressive. there was a boy who used to be ALWAYS invisible to the smart, beautiful girls of his native country.
but eventually the boy grew up, learned other languages, became a handsome young man who travelled far and wide and discovered his power also worked on smart, beatiful women of many other countries.
who? oh just someone i knew, a friend from childhood. let's not dwell on the identity of this interesting character, let's move on to the next exercise.
Not normal can mean different things. Normal is a baseline, just like average. Both links feature not normal, but extraordinary nonetheless.
In a comment above, Dov360473, who is a native speaker I believe, said that the sentence is distinctly negative. At any rate, I can’t imagine any language in the world where this sentence would be taken as positive, unless an admiring tone of voice for example were factored in. In everyday life, normality of behavior is how people discern that others are not a threat to them. An exception would be something like: “You’re not normal, you’re extraordinary!”