I see. Braids being protective made sense (I have DDs with hip-length hair. You can be sure their hair gets plaited and pinned up to protect it!), but, as my understanding is that extensions are harmful to 'white' hair, I didn't understand the brother's statement.
I don't get why white people make such a fuss over black peoples' hair! Surely the same basic rules can apply to both white and black?
Safety: keep it out of your face and out of harm's way.
Courtesy: keep it out of other people's personal space and keep it clean.
Beyond that, what does it matter?
My dc's school says: tied back if below the shoulders, no unnatural colours, no shaven heads and no extremes of fashion. They apply this across the board. I think 'shaven heads' means less than a 0 or 1. Would you consider this fair?
In the school where I work there are no regulations about hair, other than that it must be tied back for certain activities. Some of the black girls have bunches, some braids, some extensions. Sometimes the extensions are in non-natural colours. I dont think it's ever occurred to any of us to query that.
Though I have been puzzled as to why anyone would go to the hassle of extensions in 5yos' hair. Especially as they're horribly itchy (I get lots of cuddles, and in summertime the extensions really prickle me through my thin blouse.) But if they serve a purpose beyond decoration, then it does make sense.