That’s not at all a universal rule, and a low credit score can even affect employment in the US.

I understand that companies use them improperly, but that isn't he fault of the credit score. Thats the fault of the employer (or our lack of laws protecting employees). Nowhere does FICO sell their credit score product as an employment screening tool.

Paying off loans early lowers your score.

I don't believe thats true. Paying off a loan might lower your score, but I don't believe there is anything in the model that takes into account whether it is early payoff or not. Feel free to cite a source that backs your statement.

Using a credit card with a higher limit increases your score.

That's incorrect. Having a card with a high limit, and having only a small revolving balance on it (or no balance) can improve your score. Another way to achieve the same thing is multiple cards with with low to no balance that adds up to a larger total limit.

It’s never ever been a way of establishing that a person is trustworthy to receive a line of credit, it is a scam to put more people into debt and keep them there.

I'm not sure what you're saying here. If a person is able to limit their behavior in spending above a certain percentage of their credit line, then that is a pretty good objective measure someone is trustworthy of certain levels of lending to them. Do you question that?

No one opts in to have a private company collect (and lose) their private information. You’re born into a credit score.

There is no law saying that you are required be involved in borrowing. If you've never opened any line of credit, you won't have a score.