In a Pew Research Center survey of 2,849 Internet users, one out of every four women between 18 years old and 24 years old reports having been stalked or sexually harassed online.
But if one actually follows the link, one reads that "Overall, men are somewhat more likely than women to experience at least one of the elements of online harassment, 44% vs. 37%. In terms of specific experiences, men are more likely than women to encounter name-calling, embarrassment, and physical threats." [emphasis added]
That blows are rather large hole in the thesis which the poster and many others seem to be implying, that internet harassment is primarily rooted in misogyny.
This is not to in any way justify the harassment of women. But if you want to know why there's a backlash, part of the cause (not a justification, a cause) may be the ongoing distortion of the facts about violence and harassment.