The matter seems easy to be sorted out. All we need to do is to come up with an appropriate regulation. I didn't notice that until the European Championships 2013, held in Lithuania in May. It was there that I overheard a conversation between two competitors and, to my surprise, they were complaining about the referees from their own country! They said straight that the referees were much stricter with the competitors coming from their country than with anyone from another country.
Thus, it's essential to introduce the following rule into our sport. Namely, one should not referee a match of the competitor from their own country at amateur competitions such as European, or world championships.