That's their excuse. They'll take a US card if I'm actually there in
front of their machine, which seems to me to be very nearly as
susceptible to fraud.

There's a difference between 'cardholder not present' transactions and
those where you insert the card. Admittedly, the fact that you don't
currently need to sign or enter a PIN does make a bit of a nonsense of
it.

Hopefully it will soon be changed so you will have to enter a PIN, but
this will of course introduce new problems if you don't have one.
Before we got C&P in the UK, you could simply use your ATM PIN abroad
(e.g. Sweden).

Jonathan