Out of all characters they could possibly have chosen to race-swap, Snape might be one of the worst choices. It's like race-swapping the Weasley family and making them Chinese with pitch black hair even though their red hair is one of their defining features.
The problem with the casting choice isn't only that the actor is black when Snape is supposed to be pallid and British, it's that he looks like his name could be Tyrone McChadson. There's no way this athletic black guy with puppy eyes would be believable as a pasty incel with greasy curtain hair who's being bullied by James and Sirius because he's an ugly and unlovable weakling. If anything it's more likely that he'd be the one bullying them.
Obviously, Alan Rickman didn't look like Snape when he wasn't playing the role. However, with his facial features, it probably wasn't too difficult to make him look similar to the Snape that Rowling imagined when she wrote the books (though I agree with those saying Rickman was too old for the role). The new actor has absolutely nothing in common with Snape appearance wise.
Edit:
How would having black Snape being bullied for his hair and nose be racist anyway? wouldn’t it just be accurately depicting the White Supresmicist Hellscape (TM) we apparently live in? Is it somehow less racist to pretend black kids never get racially bullied now?
Just think about all the ways the story is affected by Snape being black and how the story now could be interpreted as racist.
– The black man Snape is one of the main antagonists and bullies the white boy Harry for six years.
– The white boy Harry and his two white friends keep blaming the black man Snape for everything that goes wrong at their school.
– The white man Dumbledore won't let the black man Snape teach Defense Against the Dark Arts.
– The black man Snape becomes evil because he lusts for a white woman, Lily, but she prefers the white man James over him.
– The white girl Petunia didn't want her sister to hang out with the black boy Snape.
– The black man Snape joins a wizard supremacist group, which could be interpreted as a metaphor for black supremacist groups, and they commit acts of terrorism and install a reign of terror.
