I wonder if they did it for profit or to protect themselves. If someone picked up the domain and put some dirty pictures on it, it might look bad.
if they don't make sure they have control over the domain they are "spoofing", then they open themselves up to someone else registering it and using any traffic generated to show pr0n or whatever, or maybe ads for another network (god forbid!)
also- making sure you have control over that domain ensures you don't slander a "real" website and its content. I just went to the domain you mentioned and it just has the usual placeholder for register.com
SNL should be creating some boilerplate page that links back to the show's site when you go to something like this. But they don't. oh well. I guess the Internet is just for yuks.