I always hate when "kiddie porn" is brought up as a counter-argument to something. #weak

The whole crux of the Supreme Court of Canada's decision is that, when linking to something, you have no control over the content of the destination. So today it can be a nice picture of a kitten, and tomorrow someone can change it to something defamatory and illegal.

Or today its a link to a public domain song, and tomorrow someone replaces it with something copyrighted with the same URL. You can't control that.