She is said to have hissed not whispered and the person who witnessed it, Rachel English, has written an article about it. It’s not second hand information.
I don't think you understand what "second hand information" means.
Especially considering you're responding to someone saying bullying allegations need to come from the person claiming to be bullied, which is not the case here.
Rachel English claims to have seen Meghan "hiss" at someone while surrounded by a large crowd.
If Meghan was surrounded by a crowd, how did Rachel see her "hiss"?
Rachel was too far away to hear what was said, so clearly not close.
Maybe Meghan said "I feel unsafe, get me out of here."
How exactly do you express that to a staffer, while surrounded by press and public, without "hissing"?
Why is Rachel using the word "hissing" instead of "whispering"?