If someone says they are going to do bad things to you you and they say it seriously on the internet in any other medium, it is considered cyberbullying at best and harrasment if its bad enough. Threats of violence are taken even more seriously. You need to see past the medium of the game and realize that a threat anywhere is still a threat. You wouldn't take this kind of abuse in person, and someone online who is dedicated to getting your IP address might ad well be, because they can find you.