The point that the major industries are trying to get across is that copyright infringement is just like stealing. They're saying so quite explicitly whenever I go to the movie theater or rent a DVD.
But copyright infringement is not stealing. You could make an argument about it if the period was still 14 years (i.e. the author has only 14 years to collect revenue from it, so if you want it either pay up or wait 14 years, which is doable). But that's not the case.
Because copyright is not the same as stealing a physical item, so if you want to discuss the morality of it, then length does play a role, as it should since all works should enter public domain at some point, therefore ALL discussions about copyright should address the ever-extending length.
Also, discussing the morality of copyright infringement is also important, as copyright infringement does not rob the owner of the item itself. It only duplicates it.
Because a copyrighted work is not actual property, even if they call it "intellectual property" today, but that's mostly a misnomer. A copyrighted work was supposed to return to the public domain and benefit the whole society, not just the creator, by using it and improving it.
But copyright infringement is not stealing. You could make an argument about it if the period was still 14 years (i.e. the author has only 14 years to collect revenue from it, so if you want it either pay up or wait 14 years, which is doable). But that's not the case.