Child may well be entirely innocent here, but the dad seems to have close ties with Tommy Robinson from his FB posts, and it’s entirely possible the school knew this and this influenced their decision. Maybe the speech was AI written via her dad who knows.
Her dad has posted that she will be giving her speech at a Tommy Robinson rally in London in September, so make of that what you will. I suspect there is a lot of stuff the school is aware of which the media hasn’t reported.
Could someone whose grandparents were from ,say, India, dress up in a Union flag and claim British culture is theirs on the grounds they are British? Why not? Seems this type of culture day is more divisive than celebratory. A flag is not really cultural by the way, it’s more a nationalistic symbol.