This new HBO version of Harry Potter was so close to giving us the most book-accurate adaptation possible of J.K. Rowling's novels, all they had to do was not make snape black, It makes zero sense when the books explicitly describes Severus Snape as a pale, greasy-haired, and sallow-skinned man.
Changing a character's core physical description when the entire marketing hook of this show was "unparalleled fidelity to the books" is such a massive fumble that makes no sense. If you are going to promise absolute faithfulness to the text, you can't start selectively picking and choosing which character traits to entirely delete.