A large portion of megaupload is used for piracy, nobody can deny that. Also because of how megaupload/rapidshare and other similar sites are designed, they actually store the data unlike torrents thus they do come across as "possession" of pirated material much like Kazaa/morpheus and other p2p sharing services.
Anonymous are terrorist to many governments and organizations, to go into detail they are cyber terrorist. There has been proof of them just hacking sites because they do not share the same views as the site. How can you be the "defenders of free speech/free information" and attack opposing views?
http://www.abovetopsecret.com/forum/thread661570/pg1 one of the many reasons why anonymous should be viewed using discretion.
Also any group/organization that hacks the Department of Defense and other military sites are nothing short of "a danger to national security". Especially one with malicious intent.
The whole idea of "all information should be free" is totally stupid. Do you want your whole personal information out on the web? Do you want information on how to build weapons with exact details out on the web that anybody can access? Do you want national security information be freely access to everybody, especially nations that wish to do harm to others? Not all information should be freely access but at the same time majority of the information of things such as state of the world and etc should be able to freely access to the general populace.