Interesting points, thanks for sharing.
>you might not see the necessity of keeping secrets
I wanted to address this first. I'm not a believer in "you have nothing to hide if you're not doing anything wrong", so I can appreciate the argument that some people may be more vulnerable than others. For instance whistle blowers that may need to maintain anonymity in all situations.
In these cases however, I believe some responsibility lies to those at risk to opt out of appropriate settings, or avoid using services that require tracking. Similarly, responsibility exists for the companies involved to make those opt-outs accessible, and to not use misleading language.
>Ok, lets consider insurance companies and/or banks. These businesses would really like more to get their hands on data that could give them excuses to raise your rates, deny your loan or insurance coverage.
As you said, laws do exist to protect the user against discrimination in these cases. If there's ways for companies to route around it then I'm not familiar with them, but I would imagine that opens them up to the potential of being heavily fined.
>If you think this is a theoretical concern, then you need to read about the deplorable practice known as "redlining", where data was used as a cover for racial hatred and forced segregation.
This is a good example, and certainly drives your point home. I agree it's absolutely a concern how data is collected in cases such as these. That said, open data can also be used for good. Consider medical studies that can look at entire populations for trends, or data that can help inform governments to the pain points in their region. My takeaway is that we need to be very careful about how data is aggregated and anonymized to avoid this sort of targeting.
So on that point I don't necessarily disagree with you, but my stance is that we shouldn't throw the baby away with the bathwater. Like any tool, data collection can be used for good or evil. We should be concerned with how we enable its use for evil rather than demonize the tool itself.