The point is that while it's easy to see how laws will help prosecute the bad guys you also need to consider how they can be applied to prosecute YOU. Obviously we want to stop the bad guys, and obviously you know you're basically a decent guy, and won't get harrassed, but it only takes someone to get a bit carried away, and your life could be destroyed.
It's easy to frame a law which gets the bad guy, eg patriot - "we can arrest who ever we like, without giving a reason" - that pretty much solves all law enforcement problems, so why do they need more laws? It sounds great that the government have lots of powers to deal with terrorists, paedophiles, pornographers, and photographers but unless there are checks and balances where does that leave us?
Suppose you take a snapshot of some friends down the beach. In the background someone is getting changed, and lets the towel slip. Currently it's a bit of a giggle and you forget about it. In the future, the lab guy might report it (and in the future may be compelled to report it). The next day you get a visit (just a precaution of course!). They find thousands of negatives, which of course they're unable to sort through in a reasonable time, so they seize them (just a precaution). While they're at it they'll need to take all of your equipment, including your computer.
Of course you know it's all just a misunderstanding, but you spend the next 12 months without your equipment. Your photography buisiness goes under, as you've lost all your equipment. You've no negs for reprints, and you can't even contact clients as all of your contact info was on the computer.
Of course after you've spent your entire savings on legal fee's your equpiment sudenly gets returned without an applogy, and you never hear from the police again. On the other hand word has got round the town that you've been investigated for taking dodgey (exact details a but vaugue) photo's, so you're probably getting bricks through your window by now...
Far fetched? Maybe, but if you think it can't happen, look at what happed in the late 80's early 90's to Steve Jackson, when the government decided it was time to get tough on computer crime. They passed some far reaching laws, that gave them the power to "get the bad guys", but left it pretty much up to them to decide who the bad guys were.
Ian