The cops (not to mention the services themselves - Twitter will close abuse reports if the tweets referenced were deleted, despite undoubtedly having a record of them) have a long history of not taking online harassment seriously.
What product is being promoted by this article, incidentally?
Twitter is not the police. You file charges with the police. Twitter has no authority or responsibility to file charges on your behalf.
Sarkeesian alone earned hundreds of thousands of dollars using the fiction of harassment. I'd love to see a police investigation into the veracity of her claims of being threatened. Considering how her claims of being a lifelong gamer were exposed as a complete fraud, I think we all know how her claims of being threatened will turn out.
Police have a long history of not standing up for victims, too. See https://en.wikipedia.org/wiki/Adrian_Schoolcraft, where a NYC cop was forcibly committed to a psych facility for recording evidence that his precinct was discouraging victims from formally reporting crimes to keep stats down.
One example is not a long history, and evidence not properly investigated by law enforcement is not legally admissible -- or credible -- evidence.
Doesn't it seem odd to you that not a single one of these shrill feminists complaining about rape and death threats ever goes to the police? Not one?
How are we to know that they're telling the truth, when they have so much to gain from lying, and they're caught lying all the time, anyway -- as Sarkeesian herself was?
What product is being promoted by this article, incidentally?