> On the flip side, I'm not sure how important choking it off completely really is to facebook, why get rid of ad revenue if you can pretend to chase the bad guys and keep everyone happy?

It's pretty important. In short, there is no incentive for FB to really keep "bad" ads, "fake" accounts, "spammy" pages and so on, as it creates crappy experience for user. If Facebook would be full of fake accounts, the there would be less people using it, and ads would be less effective (that means less money for FB). If there would be shitty ads, people would use more ad-blockers...

Disclaimer: I worked in Facebook's anti-spam team for couple of years.