One should not feel embarrassed for not knowing something and then asking more in order to learn.
The correct term is not embarrassment, it is inquisitiveness - which must be encouraged and not shamed
Agreed: ignorance is not embarrassing. We're all ignorant about most things.
But it is embarrassing to say something like "why'd they name iota after a Greek letter? To seem smart?" As this article explains, there is a history there and it doesn't have anything to do with "seeming smart".
I didn't know the history of "iota". I'm only vaguely familiar with APL. And I've never listened to a Turning Award lecture. This makes me ignorant. But I also didn't criticize this feature from my place of ignorance because I'm aware of it. Had I done so, it would be embarrassing.
I have criticized things from ignorance in the past, and it was embarrassing.
The point is not that you should feel embarassed by your ignorance, but that you should not feel proud about it.