While the possibilities you offered are certainly possible - you left some out.
She could have been doing exactly what she said she was doing.
She claims she was not exposed - she’s sitting in her seat by the window where very few people can see her.
They make maternity clothes now where you don’t need a blanket -the shirts are specially designed where you can pull a flap open, let the baby latch on, while the rest is covered up.
It is possible the flight attendant was just being a b&tch.
Too bad they didn’t find anyone else that was there to offer up what they witnessed.
The article says she was wearing a tee shirt "pulled down" So was the kid's head under the shirt?? Doubtful. Anyway, I agree with Lurker this is probably bitch attendant vs moonbat passenger.
MAybe nobody else DID witness it, because the woman was being discrete.