Earlier quoted context omitted.
I'm sure Facebook would like to do what you're saying, but I think that they're a long way from having those capabilities. They have billions of users, billions of ads, and trillions of pieces of metadata. Sifting through that to produce a guess like "User 1234 burned themselves and would be interested in product 5678" would be an amazing and scary piece of AI. Not to mention that Facebook are limited by the ads they…
Last year there were 29,000 categories that could be targeted. If an ad sales rep wanted to close a deal, how difficult would it be to add one more for recent burn victims, or people who recently bought a specific product? From the links that m_ke posted, facebook already has ties to loyalty card information, so it's very possible that they didn't need to do any inference, they just had the data directly. In any case…
The same could be said for any of those data streams. But just because Big F has access to those other sources of data doesn't mean it excludes voice recognition.
I'd be very surprised if FB wasn't in this arena. That's how big tech companies work these days — they do what everyone else is doing. Like getting into self-driving cars.
Apple[1], Google, Amazon, MS, etc... all have voice recognition boxes. FB doesn't need to market a box for your living room, it already has one in everyone's pocket.
([1] Apple says it doesn't use any of your Siri words against you. If you don't trust FB's word, you might no trust Apple's, either. But at least on the Mac you can keep dictation off the internet, if you choose.)