Why are so many people afraid that Google, FB, IG, read their data?

Do you know what Facebook and Google use your personal sensitive data for? Do you trust them to keep this data secure and private?

If you can't even answer the first question, don't even bother attempting to answer the second. Every-time you use Sign in with Facebook or Google, they add another datapoint from one service to your profile on their systems. Tons of users use this sign up method and Google and Facebook know what you signed up to.

Combined with their billions in cash, insurmountable data-points, users and data, they can create products that are extremely personalised and trick us into giving away more sensitive data, with their highly user-friendly (and rigorously tested) interface. It will now take just ONE username on any service and include the linked profiles and that is it.

They are now coming after your health records. Do you want them to know about that? The line should have been drawn years ago.

I'm not especially bothered that they read my data. I'm bothered that they read anyone's data. I'm a pretty boring frontend engineer who doesn't do very much, but I appreciate that there are people who aren't me whose data needs to remain private. Journalists, activists, whistleblowers, politicians, people in abusive relationships, people who are victims of crimes like stalking, etc need privacy to do things that are genuinely in the public interest, and sometimes simply to remain safe. If I accept Google, FB, IG, etc reading my data then I am condoning those companies reading the data of people who rely on privacy for more important things than I do.

Essentially... it's not about me. It's about everyone.

Well, Google and FB searches and messages respectively contain many personal secrets, so I understand having concerns about where that data is going and who might have access (although I am told the data controls are very strict).

But I do a similar question to you. Why is it that people are worried about their Google and Facebook data as opposed to the data at their health insurer or at their bank or their local government? That data is far less secure, the data security policies (if they exist) are relatively trivial. For business purposes, what a bank or health insurer might do in pursuit of money would screw up your life more than Google or FB trying to sell you stuff. Local government could certainly cost you far more money or get you into more legal trouble.

Many organisations collect and have lots of data about me.

The difference with Google, FaceBook, etc. is that they have far more data from far more different sources and they have far more money and far more power to put all together (this is the real danger) and get a picture of me, even I do not get.

And now they use this to increase their power and income and they do use this to manipulate elections, the thoughts, feelings and actions of people way more then ever in history before.

Anyone who does not fear this is willingly blind.

I am not religious, but if I was, trusting G, FB, etc, is like trusting the devil itself. Making a deal with him and selling their fortune to him.

Because of the revenue they make? Because the services they offer for free can not be compared to the money they do not pay their users? Because collecting data over the years in a shady way until the Law catches up builds mistrust?

It's not that they read the data but that they might sell it to others