It's all bollocks
If piracy hurts businesses at all, it does so in a different way than you'd think.
Suppose we have a small outfit, let's call them Cottagesoft, who sell something called CheapOffice -- a simple office suite which is more than capable of writing letters, doing accounts and keeping track of your CD collection, and which can read and write Microsoft Office files as compatibly as anyone can manage without actually having any help from Microsoft. CheapOffice retails for £50.
Now John Thomas Luser is looking for something to help him write letters, do his accounts and keep track of his CD collection. Microsoft Office sells for £500, which is more than J.T.Luser can afford. So what is he most likely to do: (1) Buy CheapOffice from Cottagesoft, and save £450. (2) Get a pirate copy of CheapOffice from the Man In The Pub, and save £50. Or (3) Get a pirate copy of Microsoft Office from the MITP, and save £500?
The end result is that Cottagesoft end up going out of business, and it's entirely due to piracy -- though nobody need ever make a single pirate copy of CheapOffice.
Microsoft have never given a flying one about rampant piracy in the past, because hey, at least people who were pirating Microsoft software were learning how to use Microsoft software. Now the competition has been eliminated, they're suddenly bothered.
I've met FAST. They visited our place of work (probably on a tip-off from a disgruntled former employee, or maybe from our main hardware supplier) trying to flog a "solution" to "prevent staff copying software from workstations". You should have seen the bloke's face when I told him that not only did we have *no* measures in place to prevent staff copying software from their workstations, but in fact we would positively encourage such behaviour! (Of course, all the software on our workstations was Open Source, but I had forgotten to mention that upfront.)
If you really want to stick it to The Man, don't use pirated Microsoft software -- use Open Source software. And if you get busted by FAST, give serious consideration switching to OSS or even manual methods.
PS. When I was at University, our AmigaSoc had an amusing alternative expansion for the acronym FAST :)