"Even on here a private message means PRIVATE. "
Wow. That demonstrates an extraordinary level of naivety of how the world we live in operates.
It's best to consider nothing private unless you only keep it inside your own head.
Especially if you think you can slip one past
any website's moderators, who on many sites, have a degree of visibility about your actions that you're not privvy too. An assumption that what you see is what the owner, or moderators can see is frequently a false one.
You may not like it, but you're using and presumably benefiting from a service for free, so it's a deal you have to put up with if you want to use those services. You are of course totally free to choose not to. Before you start screaming civil liberties, it's best to read the small print and understand that this level of moderation can also detect and prevent violence, stalking and people trafficking. It cuts both ways.
For anyone who uses the internet, it's been that way for a couple of decades. Accept it, or don't use websites.
It's a simple, free choice for yourself alone.