Copyright laws exist, and you can't get away from it. In fact, unlike in the past you don't even have an option any more to avoid copyright unless you explicitly demand that the content must be in the public domain, such as what is being done here with this "Copyfree Movement". That wasn't always the case. From a political and philosophical basis, I think the original sense of the U.S. Constitution is really a better way to deal with the issue so far as "granting for a limited time" protection to authors who "promote the useful arts and sciences". Life + 70 is not the limited time the framers of the U.S. Constitution envisioned, and protecting a gene sequence isn't "promoting the useful arts and sciences".
There is no evidence to suggest that copyright laws were ever beneficial, economically.
Certainly there is no reason to bash copyleft explicitly other than to suggest that there is a philosophically different approach going on here. Both copyleft and those putting a weak copyright license on stuff are trying to share content, the difference is how. When I copyleft my content, I am expecting that the content will remain free, which is my motive for doing so. If you don't care that it remains free, it is your privilege to open up your own content in that manner. You are also free to ignore what I make as well.
Copyleft is quite unnecessary for no other reason that non-sharing and the lawsuits of pirates imparts inferior economic benefit than the freedom of distribution and modification. In the 19th century, there were massive piracy of British literature but also patronage by players in the American literacy market. American writers were especially angry about this situation.They petitioned the government to grant British writers the same right, supposedly for the idea of an author's natural right.
Eric's Cathedral and the Bazaar illustrate the economic superiority of open source production system over closed source. The speedier evolutionary rate of open source software will eventually win over the close source. GPL is only useful if you lived in a world where the productivity difference between close source and open source are vanishingly small.
However, my position is ultimately a libertarian one. We reject copyright and patents on the ground that is unethical to coerce individuals from doing their own things with the property that they possess.