Require that every user must be shown the exact same ads (probabilistically). Don't allow any kind of interest or demographic based targeting for paid content.
Advertisers would still be able to place Ads on pages they know there target audience goes, but wouldn't be able to make those same Ads follow that target audience around the internet.
But not guess a language based on the content of posts.
Interestingly, there are autocratic governments who do try to ban vague things. The goal there is selective enforcement, not good public policy.
You don’t need to go too far down the rabbit hole. You need to introduce friction to ads.
Subscription revenues are tiny when compared ad revenue, so I expect people will resist this idea ferociously.