Actually, I suggest you check the common dictionary definitions of the term illegal, which is basically something in breach of statute. Statute can be any law passed by parliament whether the penalty or consequences fall into criminal or civil remedies. As large aspects of copyright protection are encompassed by statutes it is correct to define the sharing of copyright materials as illegal.
But this is all rather pedantic and
in this thread. If you wish to debate further the specific legal definitions please start another thread and leave this one to the Pirate Bay blockages.