It's because she's a notable figure on the internet.
I challenge the reader to find any notable figure online who has held a controversial position and not been the target of death threats.
That is an Internet anonymity problem, not a gender problem!
Women are not the only targets of anonymous death threats online!
(Not to excuse the appalling behavior of anonymous cowards who point their threats at almost every notable news target. Seriously, go read the forums on a major partisan site. Vile, disgusting, hurtful and violent language aren't the exception, they're the norm).
By playing into the gender context we're playing once against into these stupid gender arguments where they don't belong.
"But they're using anti-women language"
Of course they are! If it were a crippled man being insulted, why not imagine the language they'd use. If it was a black man being insulted and threatened, guess the language they'd use.
They pick their language to troll their target. They pick it after picking their target -- the language isn't the reason!
And yet again, a non gender issue will be filed under sexism.