In Europe, the max interchange fee is 0.3%. In the US, the average is 2%. So the relative impact of fraud is much higher.
The size of the pie being so much bigger means the issuer’s tolerance for fraud is much larger, but it’s orthogonal to whether there’s actually more fraud. In practice credit cards fraud actually impacting customers is vanishingly rare at this point.
The numbers are even public: https://usa.visa.com/content/dam/VCOM/download/merchants/vis...
If you take a look at some of the more "expensive" cards, interchange is often higher than 2%, yet issuers often pay as much only on certain categories, and flat cashback cards usually pay 1.5% (2% is relatively rare).
Compare that difference to a total interchange of 0.3% in the EU.