This does not excuse Boeing, but it's just the way it is. Training standards are higher in the US than, for example, Ethiopian airlines.
Boeing acted like there was nothing different about the new aeroplanes and therefore did not train the pilots in how to react to the new system. Indeed, that was the original point of MCAS - to avoid pilot re-training. The pilots were not trained in doing the "right thing" and so had no chance of recovering the aircraft. I don't think it's right to blame them. Regardless of whether their overall training was of higher standard, I don't think American pilots would have fared any better since they, too, would have been in the dark.