Sadly I don't find such a story that surprising, I'm saddened that it's still happening, and that bullies are still trying to silencing people from behind some cowardly anonymizing mask.
It is all too easy for someone who feels like they're entitled to be successful and powerful to feel jealousy if some "inferior" is being more successful than they so "obviously" deserve--if that "inferior" is stealing that job, or is better respected." Unfortunately threats and intimidation are all to effective at keeping those "inferiors" down.
If you're in Europe from the middle ages to the recent past, its attack the Jews. In the US South an empoverished white farmer who is feeling too insignificant can always get a jolt of some twisted sense of power by showing some poorer black people "their place" with some white masks and burning crosses.
Standing up against anonymous threats alone is terrifying, which is why the targets of this type of terrorism always need their community to say this behavior is unacceptable, and it must be stopped whenever it slimes its way up.