Plot hole
When we are introduced to barneys brother, we the viewer and robin are surprised that he's gay and black. but then it becomes clear that he's very much like barney when he shows off his suit and repeats a lot of barneys catchphrases... showing that despite their very obvious diferences they are very much alike.
But! We later learn that barneys personality was something that came about having being dumped by his girlfriend at the coffee shop, before he was a hippie. his suits and his personality changed in adult life, not something that came from his family, his upbringing....