The map is pretty biased against Germany, which is why it is brought up a lot in these kinds of discussions. Northern Italy for example has 409g/kWh and Germany 419g/kWh using production and covering the last twelve months. However Germany has 61% low carbon electricity share and Northern Italy 33%. Similar story with South Korea as well, which has also 33%, but slightly more emissions at 452g/kWh.
Because the only way you end up with these numbers, is to presume that all fossil fuel electricity is produced from the worst plant available. For Germany that would be lignite and 1075g/kWh.