I have flown out of the EU with European cadets and their skills and attitude sucks big time (go ahead and bash me, it is the honest truth). The worst of this is that they are not even aware of it. They think it is the usual in a cockpit not to follow the chain of command, argue for the sake of it, bend the SOP's, follow "what this Captain told me" instead of reading the manual, etc. It is not really their fault since they have been led to believe that it is how things are done. For them, I am the dinosaur.
Which airline was this? My guess it is one that has not the best T&C’s and does not have the option to implement a proper screening or even does P2F.
I mean, I have also flown with American and Australian pilots who had lots of hours but were pretty useless. Nationality has very little to do with it. When the market went upwards again, the good ones went to decent companies in the EU or US and the bad ones stayed or went to the second tier companies.