I personally don't think it's "ImgBurn"s place to think of every evil deed that can be executed with their software and post a request on their front page not to engage in those acts. Just like it's not Ford Motor company's job to ask people from refraining from every criminal act that can be executed with one of their vehicles.
It's silly. Should they also put up a notice requesting that no one use their software to burn kiddy porn? Do not use "ImgBurn" to transport classified information outside the United States of America? Do not use ImgBurn for x, and y, and z, and aa, and ab?
But again, it's their website, so they can post whatever they want on the frontpage. It's just 'somewhat' amusing. that's all.