Sorry I don’t get it?
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?