From my limited knowledge, there do seem to be fewer non white people in Eastern European countries. Those of us in Northern Europe have a much more mixed population, probably as a result of our colonial heritage. France, England, Germany, Holland, Spain and others were involved in colonialism and slavery and the legacy of all that, is our populations are no longer solely white.
It isn't so long ago that we had No Irish, No Blacks, No Dogs in boarding or rental properties. Thankfully, things have moved on but of course racism hasn't been eradicated.
I'm with Anja in reflecting on the growth of the right in many countries.
I'm pleased our team and their manager worked so calmly and effectively in the face of this awful provocation. What do you do with a national coach who saw no evil, heard no evil and spoke no evil and didn't even notice his captain wasn't in the dressing room at half time. I suspect you could start by sacking him and by Bulgarian politicians and sports stars speaking out to condemn what happened.
If a team has to leave the field because of racism, the side whose fans caused that should forfeit the match.