Earlier quoted context omitted.
Read the parent post again, no problem with Bulgarian people in general. What's with your xenophobia/racism haunch? It is not unreasonable to discuss such effects due to relative open - e.g. compared to US - borders. Last year in Germany I myself saw 'gangs of beggars'. While not a problem, it annoys me when on touristic places you'll get asked for money every two minutes from one of the (romanian) women with child.…
The same reason you don't say black beggars or Mexican criminals. The racial or national background of these people might be interesting for sociologists but it's unhelpful in everyday discussions. It strips people of their dignity, whether it's intentional or not. Don't be that guy.
If he hadn't said it, replies would have expressed surprise that the prosperous Swedes had resorted to aggressive organised criminal behaviour, and there would have been speculation on why that is.
There would also have been questions on why the government hasn't done anything about it yet, which he also addressed in his comment.
Stop telling us what we can and can't talk about.