[eli]

Isn't that exactly what Sony did? The whole letter is here http://gitorious.org/gitorious/dmca/blobs/master/2011-02-02....

Now, you may disagree with their reasoning or with the law, but that's a different issue

[sorbus]

They only explained why it would be illegal in the US. Gitorious is in Norway, so they want Sony to explain why it would be illegal under Norwegian law, which is the only thing that applies to them.

[shasta]

In most places, you're required to notify an infringing party that they are infringing. I've never heard of a requirement to explain the law to them.