I wonder if this might be a case of PayPal in the US vs. Europe — at least with regards to charge-backs.

It seems that the burden of proof in the EU is much higher before an issuer will allow a charge-back — at least anecdotally, the credit cards I've used require you to prove that you tried to resolve the issue with the merchant first, prior to charge-back. Even then, charge-backs would negatively impact your account standing with the issuer, so are dissuaded.