Actual paparazzi go after public figures, who have a different set of laws written for them. They forfeit certain rights to (or degrees of) privacy when they appear in public places. But they can still call the cops if someone is taking pictures of them inside their property from the street.
Can you find out someone's license plate by calling DMV? No. You'd have to walk by a person's house to get it. Being able to gather that information so easily, sitting on your ass from miles away, is different, and enters a gray ethical/legal area IMO.
It's one thing to pay for an online background check to get someone's information that you couldn't obtain through personal contact. It's another to get it for free through the most widely-used search engine in the world.
Maybe the letter of the law isn't on my side, but that's partly because legislators still don't undertand the internet yet, or how existing laws do/should apply to it. Or at least, be amended to cover it.
It just shouldn't be this easy.