There's a link in the article - looks like the kid also managed to irritate a slightly more competent black hat crew who dumped all his personal info onto Pastebin.
But in general, BK is a very competent journalist who is often able to reconstruct the identities of people in the Russian cybercrime underground. An obnoxious, pimply adolescent in Ontario was unlikely to present him with much in the way of a challenge.
I guess the answer is that there are ways of finding such things out, that I'd rather not even think about. If you're the sort of person who calls out SWAT teams to people's houses and then brags about it on Twitter, then you're probably going to be found out - either by more serious black hats, or someone like Krebs.
But in general, BK is a very competent journalist who is often able to reconstruct the identities of people in the Russian cybercrime underground. An obnoxious, pimply adolescent in Ontario was unlikely to present him with much in the way of a challenge.