Ukraine is a highly corrupt country. The worst in Europe. It is 122nd out of 180 countries, Norway is placed 4th. So that's probably not a criterium they used.
I am not sure the argument for corruption adds up, given Ukraine's global corruption perception index scores are comparable to developing nations in Africa and Asia.
Countries with high corruption have a different social contract, and it takes time for people to internalise how things are done 'over here'.