People have been warning against keeping too much funds in PayPal since 2004. Consumer protection is nearly nonexistent.
Examples of paypal being shitty abound. Why do people keep falling for it?
Surely you can take them to court (if you have time to burn)?
Absolutely correct.
Even worse, winning the lawsuit does not mean you'll see the money. It only gives you the right to do things like attach liens onto their assets. You have to actually do all that footwork (and pay the associated expenses) yourself.
So suing is a clusterfuck nightmare, and after winning, collecting what you're owed is a second clusterfuck nightmare.