Are you allowed to celebrate your culture in your country?

>English GIRL was banned from a school’s cultural diversity day — for wearing a Union Jack dress
>Union Jack, the national flag of the United Kingdom, historical association with colonialism and imperialism
>stopped by teachers who gave her the option of wearing a second-hand uniform instead
>dad Stuart Field, 47, arrived to collect her from Bilton School in Rugby, Warwickshire
>they were having a cultural diversity day and yet they singled out a group of people (English)
>they were singling out English people in England

Genuinely, are there any positives gained from Brexit?