> whenever you let someone have data about yourself, you're implicitly giving access to practically everyone

I believe there is truth in that. The way I see it is you don't have much control over information entered into any computer. You can practice good security hygiene and that means you can trust information on your personal network, but that really that means you trust your combination of OS vendor, browser, antivirus, router manufacturer, etc. A hole in any one (or more likely a combination) of these could lead to someone gaining access to your data. This applies even more to info stored in 3rd parties/data sent over the net.

Then you're at the mercy of the people who stole your data, they could very well release it to everyone, or sell to the highest bidder (and you wouldn't even know).