They kind of have it backwards. They aren’t triangulating your location, they are taking the location your connection tells them you are and tests to see if that is correct or not by checking with known servers in an area around your claimed location. It can verify you are not where you say you are, but beyond that it can’t find you. At least, not the paper the person is mentioning - this “other method” they mention doesn’t appear to be linked to any paper or anything and might just be their personal theory, not sure.