For example, imagine someone convinced by the argument "nothing to hide nothing to fear". Would this example convince them that in fact they do have to fear something? "You might think twice about contacting or meeting people (exercising your freedom of association) who you think might become “persons of interest” to the state". I do not think so, after all, average Joe does not know such people.
The solution, in my experience when talking to sceptical people not convinced of the risks is talking about money. Imagine someone with the kind of knowledge we are talking about with mass surveillance. And imagine this person could inform your insurance companies. Do you still think that you have nothing to hide? One then must only show that data is never "safe" and could always be "leaked" to make a very simple, everyday example of why it is not in my (average Joe's) interest to be continuously monitored.
I'm really still waiting to hear a convincing argument as to why I have something to hide, ideally something practical as opposed to hypothetical or philosophical.
And what if one company does this - what will other companies do? Will they keep the same price for that group as for everyone else? Then that group will leave for the company that's cheaper for them, right? Leaving the other companies with the higher-risk customers, right? So, they will have to pay out more for damages, right? Now, will they just go bankrupt? Or will they increase premiums to cover the costs?
Noone says that insurance companies aren't making inferences from data. It's just that the more data there is available to them and the more powerful computers and algorithms get, the better they will be able to model risks. And individual companies won't be able to ignore that, even if they want to. And it's the exact opposite of what insurance is intended to do: It's intended to distribute risk. The more exact insurance companies are able to model risks, the more insurance will become unaffordable to those who need it, and the cheaper it will become for those who don't need it.