The problem with this trend is that the internet isn't like real life. In real life, stealing your information is difficult. The thief would have to dig through your trash and other distasteful things, maybe even break into your house. And if they wanted to see what kinds of things you were doing, or what you liked to buy, maybe so they could sell that information to an advertising company; they would have to hire a private investigator.
And that's just for you. What about everyone else?
The internet, and the way most people use it, leaves us all much more exposed. The simplest tracking cookie can tell someone everywhere you've been, from the items pages of amazon to your private social networking profile. Anonymity on the internet keeps us safe by making it that much harder to mine accurate information.
Remember that (Brazilian) woman who had her insurance revoked after the insurer learned that she had pictures on (a friend's) facebook account, wherein those pictures she was smiling and having a good time, so she (obviously) must be cured of her major depression. Reality is much different. The not-drug treatment for depression is socialization, and everyone smiles for the camera. I hope she sued the balls off of that company, but I never followed up on that story.
This is just an example of the damage that a company (which most people would agree is a legal one) can cause by abusing the exposure people face on the internet. What would less scrupulous individuals do if the internet lost anonymity? I'm sure it wouldn't affect anyone using it criminally. They'd simply get a proxy service or make their own. Suddenly, your information would become even more valuable, and you might get blamed for crimes you didn't commit if someone used your information to slander another person.
The internet allows anonymity for a reason. It must stay free and open and anonymous.
Demanding to change that is folly, and the laws that allow for this kind of criminalization of the service providers are trying to do just that.