Yes...its Russian culture in that they are incredibly racist against blacks. So he is ignorant to the sensitivity at that time in his life. He is a 19 year old white russian young man.
Is it right? No. Is it racist? Yes? Should we blame Artemi? No...we should educate him, let him get older and wiser, and forgive him. He feels that way because of every joke and opinion of his peers since a young age.
Look at Pau Gasol and the ignorance of the Spanish team toward Chinese jokes. Look at the reports of bananas being thrown. In the 2014 World Cup there were several issues with Russia, Poland, and black players that came to the forefront of discussion. When a black player on a European club visits parts of Poland and Russia precautions, security, education, and pleas for decency ensue.