For some of us, the question isn't a trademark worry, but a life and death question of avoiding stalkers. For some, it's a question of harrassment lawsuits designed to destroy free speech.
It's one thing for a business to have contact information on the Internet publicly available. The executives and their beloved families don't live at the corporate address. If they did, they'd be howling about their privacy. If ICANN made a rule that all executives of all corporations must provide contact information for their home addresses and provide their home phone numbers to apply for a domain name, you'd have the equivalent of what bloggers are being asked to submit themselves to.
Bloggers live where they work, at home. Providing that kind of contact information publicly is a way of setting them up for identify theft, stalking, stupid lawsuits, and the fear of never knowing when some net kook is going to show up on one's doorstep. Most bloggers have families, children they wish to protect from kidnapping or other horrible things. In other words, anonymity doesn't reflect a desire to be mysterious. It really is a question of safety.