There are no private spaces online, because your privacy is only protected by the people who own the servers. Your data isn't private to them, nor any governments who can compell them.

You cannot trust that any data you put on services, that you're not completely in control of, is going to remain private.

There are countless examples of services selling your data, hackets getting access to your data or governments compelling a service provider to produce your data on demand.

The exception to that are services where you can enforce your privacy through well implemented encryption.

For exsmple, I don't need to trust a cloud storage provider that is storing my data because it's encrypted on my machine using keys that only I control prior to being stored. My privacy doesn't require me to trust that Google will protect my data from insiders, hackers or hostile governments because they don't have the ability to produce it. My privacy is protected by the laws of mathematics regardless of how compromised the service provider is.