As far as the account fraud is concerned, I've wondered about this throughout the tech industry for pretty much my whole career. Most companies I've worked for have done all kinds of things to pad usage and retention stats in order to appease investors, ranging from ethically innocuous to "holy shit I need to start looking for a new gig". Online advertising in particular has been the worst at this in my professional experience.
What's being communicated to the advertiser isn't the whole truth: it's a selectively, surgically crafted subset of the truth. The first time I saw "The Big Short", I couldn't help but think about how similar the ad company I worked for behaved like the credit rating agencies. We knew that if our reporting showed that we were ineffective, we'd lose customers, so we did all kinds of things to make the reporting look good.
The accusation that one of the largest companies in the world is doing pretty much the same thing doesn't surprise me at all.