I'm having trouble understanding the coherence of this argument. So let's list the points:
Claim: Sony is down because they are protesting SOPA.
If Sony Music is in favor of the bill (and I recall seeing that they were), I highly doubt Sony's gaming division would publicly fight against it. That kind of internal strife is the kind of thing that destroys corporations.
Also, if Sony was down for protest reasons, they would make that highly public... not secret. According to news recently reported around the web and on this site, the issues striking PSN right now are from an unknown source. They wouldn't create a scenario that damages their credibility in sake of a protest; they'd try to make it seem like they're the good guys and that we should support them.
So yeah, I really don't understand this argument whatsoever.