Technically, Black Spermatazoon isn’t wrong. The Japanese name refers to the sperm cell specifically. Same with Centochoro, and even King the Ripper - it feels like ONE meant to make it a play on Jack the Ripper.
I guess it just feels like Viz intentionally makes these names so that, if someone Googles them, they only get the Viz versions and not the fan translations. Viz has the right to do it, sure, but should they?