Let's not be sniffy. If some European cards can offer 0% or 1% surcharges, the question must be, why can't US cards?

Amex seems to be 2% generally. Some UK Visa and MasterCard cards charge a whacking 2.75% (as Pianist suggests, this is not always clear), others charge 0%, 1% or even 3%.

The Visa charge of 1% mentioned above is included in these surcharges, except that there is no Visa charge within Europe.

The Visa card I use outside the UK (Frizzell Bank) charges 0% in Europe and 1% outside Europe, i.e. only the Visa charge. It also donates 0.5% to the (UK) Cancer Research Campaign, so apart from saving money, there's even a feelgood factor.