> As a technology, it is just database joins

Which don't work out all that well in practice.

> on top to provide global visibility into any system.

Global visibility into the data. There's no guarantee your data and your performance match. We have so much data the quality of much of it is fairly low.

> Tech is tech and can be used for both good and bad.

You can also just lie about what you're doing and use it as a cover for violations of civil rights and federal law.

I mean, if it's just "database joins," then why is the government buying this from a vendor? Shouldn't they just be able to _do that_?

That’s called MakeOrBuy.

Why do everyone go to Facebook [/or HN] instead of self-hosting their blog?

Because Facebook [/or HN] is a bunch of highly skilled experts that have shaped the proper UX for ubiquitous information exchange between humans [/ geeks].

So we, the users, can concentrate on our own business [/ trolls].