1. In the US, the Genetic Information Nondiscrimination Act already prohibits this. For other things, like "are you a skydiver", the insurance company already has the right to ask you that.
2. I mean, sure, I'm sure I've broken some laws, but I can't think of any examples of overly agressive prosecutions for people who weren't already guilty of bad shit.
3. I mean, people are already used to creepy hypertargeted Facebook ads, most of them have don't really care anymore.
4. I mean sure, but how does this affect me?
5. This just sounds like a hand-wavy slippery slope argument.
I think the issue for most people in the US is that they still fundamentally believe that the justice system is generally "just", at least with respect to themselves, though that is obviously changing. Contrast that with Germany, where people are vividly aware of what happens when the government uses personal data nefariously.