Facebook’s terms of service are pretty clear, by the standards of such things. (I should know: I once read 150,000 words of small print in a week to see what I would find out.) There are very few random blocks of all-caps, it’s fairly short, and it has hyperlinks in it. You don’t even have to scroll down to find one of the key sections, which lays out what it means when you share information with Facebook.

“You own all of the content and information you post on Facebook,” the company assures you, “and you can control how it is shared through your privacy and application settings.”

So who is Facebook to tell me that I can’t share the information I own and I control with a company that’s offering me a hefty discount for doing so?

But that’s what Facebook did today, in response to insurance company Admiral’s plan to let young drivers share their Facebook posts to prove they are low-risk.

Let’s be clear: Admiral’s plan isn’t something I was fighting to sign up for. For one thing, I don’t drive and have zero posts on my Facebook account. Not quite the target market, there. But there are more generalised reasons to be wary: Admiral’s bizarre pseudoscientific claim that exclamation mark use indicated a bad driver, for instance.

I’m also not eager to contribute to the erosion of risk-pooling which lies at the heart of the entire concept of insurance. And, frankly, there’s something of the surveillance state about your every personal action having a financial consequence as it gets filtered through the corporate realm.

Despite that, is Facebook really fighting my corner? The company forced Admiral to pull its test product, citing section 3.15 of the company’s platform policy – the rules under which apps are allowed to plug in to Facebook’s site. Those rules are clear: Facebook data should not be used to “make decisions about eligibility, including whether to approve or reject an application or how much interest to charge on a loan.”

In a statement, Facebook celebrated its rejection of Admiral: “Protecting the privacy of the people on Facebook is of utmost importance to us. We have clear guidelines that prevent information being obtained from Facebook from being used to make decisions about eligibility.”

But it’s hard to see how the privacy of people on Facebook has been protected. Admiral’s software was opt-in, ensuring that the company saw nothing its customers didn’t share with them. What’s more, the software plugged into Facebook with a single, explicit, well-communicated purpose: scan your Facebook profile to find out if you’re eligible for discounts on your care insurance.

Compare that, for instance, with the permissions required to play even a simple game. Words With Friends, for instance, asks for your public profile, friends list, and email address before you can play it. Does a scrabble clone really need to know my age and gender? Wouldn’t a site that cares about privacy crack down on that, first?

The fact is, Facebook isn’t really acting based on Admiral’s invasion – or not – of users’ privacy. It’s acting because Admiral has violated Facebook’s exclusive right to be the only company that uses Facebook data to discriminate.

If Facebook cared about unfair profiling and privacy abuse, for instance, it would probably not have started grouping its users together based on their “Ethnic Affinity”. It wouldn’t then allow that ethnic affinity to be used as a basis for excluding users from advertisements, and it certainly wouldn’t allows that ethnic affinity to be used as a basis for potentially illegal discrimination in real estate advertising.

If Facebook cared about the privacy of its users, it wouldn’t strain as hard as it could to suggest “people you may know” based on the slimmest of inferences. It certainly wouldn’t go so far as to recommend that patients befriend other people who visit the same psychiatrist as them. That seems like a far bigger privacy breach than willingly letting your insurance company read your posts.

There may be a simpler reason why Facebook doesn’t like like the Admiral. If you realised you could get a discount on your car insurance by being cautious about what you post, you might make fewer personal posts, you might fewer spontaneous posts, or you might just make fewer posts. Facebook has already seen a decline in what it calls “personal updates” – that’s you or I actually writing a Facebook post, rather than simply sharing a link or liking a picture – and it could be scared that that trend could continue. If our visits to the site drop, Facebook’s share price could go the same direction.

So don’t fool yourself. Facebook isn’t fighting in your corner against an evil insurance company (even if that insurance company isn’t exactly on the side of angels either). It just wants to make sure you don’t think twice next time you post “Just got drunk and texted all my exes!!!! Think I’m going to get a tattoo next!!!”