I think people are being a bit hysterical. I remember the same thing happening when the DMCA was passed. The government just wants to end flagrant abuses of piracy. I don't think they are going to sic their dogs on Reddit. Sites like YouTube are already in compliance. So, I think it does smack of conspiracy theory, yes.
The trouble is that SOPA doesn't require government intent to cause site closures; a copyright holder must merely send a letter to a site's advertising agency or payment processor to cause its funds to be cut off in five days. No court order required.
Now, the criteria is that the site is "dedicated to the theft of US property", but advertising agencies and payment processors are held immune to liability for actions they take under the law, so they have no reason to verify that the site is, in fact, dedicated to theft before shutting it down.
There does not need to be an active government conspiracy for this to harm websites.
Interestingly enough, if you bothered to read the comment by reddit's admin you would note that the DMCA has increased the cost of running reddit. We've also seen the DMCA abused by media companies to take down content they have no rights to. Usually, these cases involve a victim without the money to hire lawyers to fight it.
There were never claims that the DMCA would literally shutdown sites like youtube and reddit. But the criticisms of it certainly seem justified in hindsight.
Yes ending flagrant abuses is the stated goal of the bill, but the methods it uses toward that end leave lots of unintended consequences which will be very, very damaging. Those in support of the bill either haven't taken the time to understand those consequences or simply don't care.
The conspiracy theory is that the unintended consequences are in fact intended by the MPAA/RIAA. Given their past and present behavior, it's not a stretch.
