To clarify, it isn't a Nazi regime according to these criticisms, but the argument is that there is a strong current of Nazi and Nazi-sympathetic ideology in Ukraine, which historically is true (it is also true of Russia). As to the question of how a country with a Nazi problem could elect a Jewish president, it may be worth asking how a country that struggles with systemic abuse of Black people like the US elected a Black president. Poltical and ideological currents are hard to pin down and electoral results may not tell a complete story.