strange usage of いけない


there is a line in the song 徒花の涙 by ウォルピスカーター that is really hard to
understand for me:

> 一人っきり あの子は泣いていた  
>  逃げ出した過去の無力 思い出して  
> 大切な記憶を ひた隠し  
>  **生まれてはいけなかった** と泣いていた  
> 事変の荒波が 畝りをあげてゆく

usually ていけない is used in situation in which you suggest or warn someone not to
do something, but in this case, if you apply this logic to that sentence, the
translation will become nonsense:

> I was crying because being born was forbidden

are there any plausible explanation?




～てはいけない is much broader than simple permission. It can express that, but
ultimately, it expressed that something shouldn't or mustn't be done for
whatever reason.

あの子 (I think, rather than 'I') was crying because 'they should never have been
born', perhaps believing that if they hadn't been, some painful events in
their past wouldn't have played out the way they did.

