Why is “blauäugig” used with a negative connotation?

Question

Still today the cliche of a German is being tall, blond and blue-eyed. Surprisingly the expression "blauäugig" is most often used with an obvious negative connotation:

Professor Otmar Issing, der ebenfalls die Regierung berät, kritisierte den Vorschlag als blauäugig und wenig erfolgversprechend.^{Süddeutsche Zeitung}

Wenn Paare erfahren, dass sie ein Kind bekommen, werden sie meist ziemlich blauäugig. Sobald der Schwangerschaftstest positiv ist, scheinen dem Geldausgeben keine Grenzen mehr gesetzt.^Spiegel

Zu glauben, damit wäre bereits alles ausgestanden, ist mehr als blauäugig.^Focus

Are blue-eyed Germans different or may there be another origin of this expression? Do people with blue eyes feel discriminated by the usage of "blauäugig"?

Answer 1

This comes from the fact that newborn do have blue eyes, without exception. Since newborn are obviously unacquainted with everything, blauäugig sein means to be naive, unexperienced and credulous.

Here is a quite good explanation which points out:

Blauäugig sein bezieht sich also auf die Unbedarftheit eines Kleinkindes.

Answer 2

Em1 already answered the origin of the word. I would like to comment on your question about discrimination:

Do people with blue eyes feel discriminated by the usage of "blauäugig"?

One could think that this is somewhat similar to blond people and the prejudice about them being stupid. But my perception is that "blauäugig" does not carry any assumption about grownup people with blue eyes. This is the reason why I would not feel discriminated against if I (still) had blue eyes. I am however well aware of the origin of the word (and the connection to newborns).

So I could imagine that people might have some idea that blauäugig is somehow connected to this "blondes are stupid" cliché because blond people often happen to have blue eyes.