The problem, I think, is that we need to discriminate between maybe-questionably-fair-use copyright infringement (like sharing) and real, for-profit, hawking of pirated goods.
Daniel Defoe used the word piracy in this sense way back in 1703, so I think there is precedence.
Yes, although alternative terms like "forbidden sharing" aren't quite as catchy and don't have the associated glamour factor from dramatic swashbuckling movies.
What's wrong with "copyright infringement"?
no. Because the people that don't want the term piracy used think that way because they don't feel what they are doing is wrong.
Or possibly because they believe that what they're doing isn't much like "a war-like act comitted by private parties that engage in acts of robbery and/or criminal violence at sea," and there is probably a more descriptive term. ( https://secure.wikimedia.org/wikipedia/en/wiki/Piracy )
Do you really believe anyone in the year 2011 thinks it means that? Words change meaning over time and there's not much you can do about it.
Does gay mean happy? or does it have some other meaning?