Even if SOPA/PIPA/ACTA arent that "bad" on the first glance what do you think will happen in 1, 5 or 10 years? Generally its that ones such laws are passed they open a passage for argument. We in Germany had a similiar discussion on "Banning" sides with Childporn and Terrorism and it was said that only those sides there to be blocked. Anyway pretty soon other interest groups sprung on the wagon, our RIA/MPAA like organisations demanded that for copyright infringement there should be bans and then come along people that wanted blocks for other stuff etc. etc. Thankfully the protests here axed this law for the time being.
So imagine these things are passed? What then? Are you thinking politicians are ever going to revoke those laws? Hell no, that would make look them weak and giving into the demands of "Pirates", "Thiefs", "Rapers", "Terrorists". Instead they go on extending this bull, taking money from interrest groups and what not that want more and more control over content. Why? Because it shows muscle, actionism. How many parts of the population would be for revoking penalties on drug use and ownership? How many part would be for harsher penalties? Joe average is happy when a Weed-junkie is prison while he can keep drinking his 6t can of beer because he feels "safer" now while he searches for the keys of the car.
And while we are at why not just ban some webpages that are not conforming with the Government/regime? Do you realy think everyone in any Government is good enough to do not just that? SOPA and co are a very handy excuse.
edit:
Oh and Laying of SOPA does not mean it is never to come back. This a test-balloon tactic. You propose a very harsh law and you get opposed or not. If not you are lucky, if you are, you are not in any trouble at all. Just wait a couple of weeks the population will be feed up on hearing all that is perciefed as "whining". If there are still problems and resistance you can water the Law down and then down again as often as you like. Moist laws are tailored in a way that most of is just extra-miles after the real goal. And heck you can still count on some Nutjob wanting to profilate him/herself as "strong" and "acting" in the eye of the voter.
edit 2: i am sorry for ranting this much.