I can understand her daughter being picky. I have an 8 year old who is very fussy, despite being weaned on everything going and having a very diverse range of food at her nursery. I think it's just one of those things - some kids are fussy, some aren't.
However, there are ways to manage it and encourage more diversity - but literally everything I have read says it should be low pressure... Making a bloody reel about it for your thousands of followers is not low pressure, that poor girl. And yes, eat at the table not on the sofa with a fold up table in front of the TV!