I personally think a mother should be free to do it anywhere. But I also think it's not too much to ask that some kind of shawl is used or a nursing top which is discreet.
Because it perpetuates the notion that feeding, or breasts doing what they're actually for is in some way shameful. Particularly ridiculous because if you open any page of the inflight magazine you're likely to see an advert for something or other that has far more visible boob in it.
The issue is not with the person feeding but with the one who is offended.
So instead, I don't really see a problem with asking the person complaining to cover their head so they don't have to look. In fact, if someone is offended by gay people, they could do the same. Personally I'm hugely offended by nose picking, but I just don't look.
I've said this before - but the post was deleted, KLM Reservations/Social Media team is not based in the Netherlands and so could explain this "uninlightened" and clearly accidental tweet.