I've lived in Finland decades ago and it was very different from where I came from - clean so to speak. Even in Helsinki Weed was hard to come by. No weird guys lurking on corners and all this scum one encounters in big cities in the wrong districts. There were no wrong districts. Scandinavia is/was (?) a different culture also because it was not riddled with such untethered people.
In this case, the comment is accusing you of summoning a dog with your dog whistle, while meaning that your comment is subtly racist.
For what it's worth, I don't really agree. The bombers are largely second or third generation immigrants, and I read you as implying they weren't ethnic Swedes - which is true. I don't see how the truth can be racist.
What is an ethnic swede? Does it have to do with blood purity, skull proportions, or some other definitely racist concept? Or, does it have to do with cultural assimilation and broad acceptance into the ethnic subgroup?