But the bill would give software companies the same tools to go after warez sites too. Why wouldn't Adobe want to be able to crack down on sites that distribute cracked copies of Photoshop? Or Microsoft with illegal copies of Windows or Office?

That's not to say this is a good bill. It's not. But if it's in the interests of companies with significant IP to protect to support it, companies with significant IP to protect like Microsoft, Adobe, and Apple can be expected to support it.

Their support is really that simple.