I don't think laws are really needed. I think enforcement is. There's no excuse for saying something to the effect of "I'm going to rape you tomorrow." That's already against the law in any civilized place. What the internet world needs is a few high profile cases of men who think they are invincible and free to persecute to get the book thrown at them. Obviously there's a grey area as to what constitutes trolling and what crosses the line into harassment, but there's no such thing as free speech when it comes to specific threats.
All I can think is: that sucks for the few high profile people who end up in prison for years because of a tasteless joke. Hopefully those who get the book thrown at them are truly menacing human beings, not a neckbeard in mommy's basement who has no actual violent will towards women.
Personally, I wouldn't give a fuck. Actions have consequences. If some dipshit has to go to jail to be made an example of, then so be it. It's not even correct, IMO, to refer to this type of thing as a bad joke. There's no context in which telling a stranger you're going to rape them is funny.